Photocurable thermosetting luminescent resins

ABSTRACT

Photocurable luminescent polymers are prepared from thermosetting unsaturated polyesters, suspending fillers, phosphorescent pigments and photocatalysts and utilized to make gel coated articles and molded, cast and fiberglass reinforced plastic (FRP) articles. The luminescent polymers show bright and long-lasting photoluminescent afterglow, strong thermostimulation of afterglow by heat and electroluminescent properties.

[0001] This is a continuation-in-part of application Ser. No.09/766,415, filed Jan. 18, 2001, currently co-pending, which is adivisional of application Ser. No. 09/170,432, filed Oct. 13, 1998, nowissued as U.S. Pat. No. 6,207,077, Mar. 27, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to luminescent synthetic polymers.More particularly, the invention relates to photocurablephotoluminescent, thermoluminescent and electroluminescent polymerblends useful as gel coats and as moldable resins.

[0004] 2. Description of Related Art

[0005] The term “luminescenz” was first used in 1888 by EilhardtWiedemann, German physicist and historian of science, for “all thosephenomena of light which are not solely conditioned by the rise intemperature.” By the rise in temperature, Wiedemann referred to the factthat liquids and solids emit more and more radiation of shorter andshorter wavelengths as their temperature increases, finally becomingperceptible to the eye as the material becomes red hot and then whitehot. This is incandescence or “hot light,” in contrast to luminescenceor “cold light.”

[0006] Examples of luminescence are the dim glow of phosphorus (achemiluminescence), the phosphorescence of certain solids (phosphors)after exposure to sunlight, X-rays or electron beams, the transitoryfluorescence of many substances when excited by exposure to variouskinds of radiation, the aurora borealis and the electroluminescence ofgases when carrying a current, the triboluminescence of crystals whenrubbed or broken, the bioluminescence of many organisms, including thefirefly, the glowworm and the “burning of the sea,” the fungus light ofdecaying tree trunks, and the bacterial light of dead flesh or fish.

[0007] For centuries incandescence was the universal method ofartificial illumination: the torch, candle, oil lamp, gas lamp andtungsten filament served to light the way. There remains a need for auseful, renewable cold light source, particularly for photoluminescentmaterials which will absorb light and then emit useful amounts of lightover long periods, thermoluminescent materials in which thephotoluminescence is activated by heat and electroluminescent materialsin which the light output is in response to electrical current.

[0008] Phosphorescent pigments are those in which excitation by aparticular wavelength of visible or ultraviolet radiation results in theemission of light lasting beyond the excitation. After cessation ofluminescence and renewed exposure to light, the material again absorbslight energy and exhibits the glow-in-the-dark property (anabsorbing-accumulating-emitting cycle). Most phosphorescent pigmentssuffer from the problems of low luminescence and/or short afterglow.

[0009] Various phosphorescent substances are known, including sulfides,metal aluminate oxides, silicates and various rare earth compounds(particularly rare earth oxides). The most common type of phosphorescentpigment is zinc sulfide structure with substitution of the zinc andactivation by various elemental activators. It is known that manyluminescent materials may be prepared by incorporating metallic zincsulfide (which emits green light). Moreover, with zinc sulfide amaterial or mixtures of materials variously termed activators,coactivators or compensators are usually employed. Known activatorsinclude such elements as copper (forming ZnS:Cu, probably the mostcommon zinc sulfide phosphor), aluminum, silver, gold, manganese,gallium, indium, scandium, lead, cerium, terbium, europium, gadolinium,samarium, praseodymium or other rare earth elements and halogens. Theseactivators presumably enter the crystal lattice of the host material andare responsible for imparting the luminescent properties to thematerial. Other sulfide phosphors which emit various colors of lightinclude ZnCdS:Cu and ZnCdS:Ag, CaS:Bi, CaSrS:Bi, alpha barium-zincsulfides, barium-zinc-cadmium sulfides, strontium sulfides, etc. Theother important class of long-life phosphorescent pigments is the metalaluminates, particularly the alkaline earth aluminate oxides, of formulaMAl₂O₄ where M is a metal or mixture of metals. Examples are strontiumaluminum oxide (SrAl₂O₄), calcium aluminum oxide (CaAl₂O₄), bariumaluminum oxide (BaAl₂O₄) and mixtures. These aluminate phosphors, withor without added magnesium, may be further activated with other metalsand rare earths.

[0010] For example, U.S. Pat. No. 5,558,817 (1996) to Bredol et al.discloses a method of manufacturing luminescent zinc sulfide of cubicstructure activated by copper and aluminum, forming a material having ahigh x-value of the color point as well as a high luminous efficacy inconjunction with a simple manufacture. U.S. Pat. No. 3,595,804 (1971) toMartin, Jr. discloses a method for preparing zinc sulfide andzinc-cadmium sulfide phosphors containing aluminum and activated withsilver or copper. U.S. Pat. No. 3,957,678 (1976) to Dikhoff et al.discloses a method of manufacturing a luminescent sulfide of zinc and/orcadmium. The luminescent sulfide may be self-activated or activated bysilver, copper and/or gold and coactivated by aluminum, gallium, indium,scandium and/or the rare earths. U.S. Pat. No. 3,970,582 (1976) to Fanet al. discloses luminescent materials comprising alpha barium zincsulfides or barium zinc cadmium sulfides activated with manganese,europium, cerium, lead or terbium and methods for making the phosphors.

[0011] Alkaline earth metal aluminate oxide phosphors and theirpreparation are discussed in U.S. Pat. No. 5,424,006 to Murayama et al.Alkaline earth aluminum oxide phosphors of formula MAl₂O₄ were preparedwhere M was selected from calcium, strontium, barium or mixturesthereof, with or without added magnesium. The phosphorescent aluminateswere activated with europium and co-activated with lanthanum, cerium,praseodymium, neodymium, samarium, gadolinium, dysprosium, holmium,erbium, thulium, ytterbium, lutetium, tin, bismuth or mixtures thereof.These metal aluminate phosphors have a bright and long-lastingphotoluminescent afterglow and show a glow peak of thermoluminescence ina high-temperature region of 50° C. or above when irradiated byultraviolet or visible rays having a wavelength of 200 to 450 nm at roomtemperatures.

[0012] The alkaline earth metal type aluminate phosphors of Murayama etal. were developed in response to the problems with zinc sulfidephosphors decomposing as the result of irradiation by ultraviolet (UV)radiation in the presence of moisture (thus making it difficult to usezinc sulfide phosphors in fields where it is placed outdoors and exposedto direct sunlight) and problems of insufficient length of afterglow(necessitating doping a radioactive substance to the phosphorescentphosphor and employing a self-luminous paint which keeps emitting lightby absorbing radiation energy for items such as luminous clocks). Themetal aluminate phosphors such as activated alkaline earth aluminateoxides exhibit UV insensitivity and bright and long-lasting afterglowluminance. However, metal aluminate phosphors may be at a disadvantagecompared to zinc sulfide phosphors in requiring a considerably long timeand/or more intense illumination for excitation to attain saturation ofafterglow luminance and vulnerability to water and moisture. This pointsout is the need for adaptation of specific phosphors and mixtures ofphosphors for use in varying excitation conditions, a need forwater-resistant formulations suitable for protecting phosphorescentparticles and a need for UV protection where sulfides are utilized.

[0013] Phosphorescent materials have found use in a variety ofcommercial applications including warning signs, machinery marking, dialillumination, directional signs, marking the edge of steps, firehelmets, accident prevention, protective clothing, sports equipment,etc. Commercially available sheets of phosphorescent material aretypically phosphorescent pigment in clear polyvinylchloride. Otherapproaches are also utilized, usually involving thermoplastics (whichmay be repeatedly softened by heating and hardened by cooling) orelastomeric and rubbery materials.

[0014] For example, U.S. Pat. No. 4,211,813 (1980) to Gravisse et al.discloses photoluminescent textile and other flexible sheet materialscoated with a thin film of photoluminescent synthetic resin. A textilematerial was coated with a synthetic resin containing a phosphorescentmetal sulphide and a substance which absorbs energy of short wave-lengthand emits energy at wave-lengths which lie within the absorptionspectrum of the phosphorescent constituent. Preferred resins werepolyurethane resins, polyvinyl chloride resins, polyacrylates and/oracrylates, elastomeric silicones and combinations of these resins. Thepreferred phosphorescent sulphide was zinc sulphide, with calcium,cadmium and strontium sulphides also being utilized. U.S. Pat. No.5,692,895 (1997) to Farzin-Nia et al. discloses luminescent orthodonticappliances. A preferred orthodontic bracket material comprises a plasticmaterial, preferably polycarbonate, glass fiber reinforcement andluminescent pigment, preferably zinc sulfide doped with copper or zincsulfide doped with copper and manganese. U.S. Pat. No. 5,605,734 (1997)to Yeh discloses a method of making carpet with phosphorescentdirectional signals and signs. Symbols were tufted into the carpet usingpolymeric filaments and fibers containing zinc sulfide copper activatedpigments.

[0015] U.S. Pat. No. 5,698,301 (1997) to Yonetani disclosesphosphorescent articles composed of sequential layers of a transparentresin layer containing no UV light absorber, a phosphorescent layerutilizing SrAl₂O₄ as the phosphorescent pigment and a reflective layer,with an optional adhesive layer backing on the reflective layer. Thetransparent resin layer may be materials such as polycarbonates, acrylicresins, polyvinyl chlorides and polyesters. The phosphorescent layer iseffected by dispersing the phosphorescent pigment in a varnish preparedby dissolving one of the above resins (preferably an acrylic resin or avinyl chloride-acrylic copolymer resin) in a solvent and printing ontothe transparent or reflective layer. U.S. Pat. No. 5,674,437 (1997) toGeisel discloses methods of making luminescent fibrous material bycombining a metal aluminate oxide pigment with a thermoplastic polymer,which is heated, mixed and extruded into fibers. The luminescentcomprises a thermoplastic polymer such as polypropylene, polyamides,polyesters, polymethacrylics, polyacrylates, polycarbonates,polycyanoethylenes, polyacrylonitrides, polyvinyl chloride,polyethylene, polystyrene, polyurethane, acrylate resins, halogenatedpolymers or mixtures. The metal aluminate oxide pigments are selectedfrom strontium, calcium or barium, with or without magnesium, andcontain a europium activator and a co-activator of lanthanum, cerium,praseodymium, neodymium, samarium, gadolinium, dysprosium, holmium,erbium, thulium, ytterbium, lutetium tin or bismuth. A plasticizer isalso added. U.S. Pat. No. 5,607,621 (1997) to Ishihara et al. disclosesmethods of making phosphorescent resins and formed articles. Thephosphorescent comprises a resinous material such as acrylic resin, ABSresin, acetal homopolymer or copolymer resins, PET, polyamides such asnylon, vinyl chloride resin, polycarbonates, polyphenylene oxide,polyimide, polyethylene, polypropylene or polystyrene, an SrAl₂O₄phosphorescent pigment and a liquid paraffin activator. Thephosphorescent resin mixture was kneaded at a temperature higher thanthe melting point of the synthetic resin and extruded to produce pelletsfor injection or extrusion molding.

[0016] U.S. Pat. No. 5,716,723 (1998) to Van Cleef et al. discloses glowin the dark shoe soles of rubber (a styrenic block copolymer orbutadiene block copolymers), processing oil (plasticizer or extender),stabilizer (ultraviolet stabilizers, antioxidants and/or preservatives)and phosphorescent material (preferably zinc sulfide copper compounds).Optional ingredients include flow modifiers, modifying polymers andfillers. U.S. Pat. No. 4,629,583 (1986) to Goguen also disclosesphosphorescent polymer-containing compositions suitable for use inshoes. The composition includes an elastomeric polymer, a processingoil, a stabilizer and a phosphorescent pigment (preferably a zincsulfide copper compound), with optional modifying polymers, dry blendflow modifiers and fillers. The elastomeric polymer is preferably astyrenic block copolymer, monoalkenylarene copolymer or polystyrenepolybutadiene block copolymer. Preferred modifying polymers includedhigh density polyethylene, ethylene vinylacetate, polybutadiene resins,high styrene resins, poly(α-methylstyrene) resin, crystal polystyreneresin, high impact styrene polymers and co-polymers and mixturesthereof.

[0017] Numerous other plastic articles containing phosphorescentmaterials are also known. For example, U.S. Pat. No. 3,936,970 (1976) toHodges discloses light emitting fish lures. The luminescent materialcomprises a phosphor such as zinc sulfide, an extender such as magnesiumcarbonate for increased luminous life, a suspending agent such as silicaand zinc palmitate and a carrier for the luminescent material such as atransparent or translucent plastic. U.S. Pat. No. 5,490,344 (1996) toBussiere discloses glow-in-the-dark fishing lures made by combining awhite powder with a plastic resin and a phosphorescent substance.Typical resins include thermoplastic rubber, styrenics, polyolefin andplastisol. U.S. Pat. No. 4,759,453 (1988) to Paetzold discloses a babybottle marked with a luminescent marker band made of synthetic plasticto which has been added an inorganic zinc sulfide phosphor with doubleactivators. U.S. Pat. No. 4,210,953 (1980) to Stone discloses aflashlight having a luminescent case, band or sleeve containing a zincsulphide or zinc-cadmium sulphide phosphorescent material.

[0018] Polymer epoxies were utilized in U.S. Pat. No. 5,395,673 (1995)to Hunt, which discloses a composition useful for non-slip groundsurfaces where lighting conditions may be poor. The compositionpreferably includes a polymer epoxy (diglycidyl ether resin aliphaticamine adduct modified with amyl ethyl piperidine as a stabilizer), aphosphorescent pigment (preferably copper activated zinc sulfide)and anaggregate such as aluminum oxide.

[0019] A much different approach, which points out the need for improvedthermosetting luminescent resins, was taken in U.S. Pat. Nos. 5,135,591(1992) and 5,223,330 (1993) to Vockel, Jr. et al. These patents discloseprocesses and phosphorescent fiberglass reinforced plastic articles inwhich a phosphorescent pigment is first applied to the reinforcingfabric using a carrier resin and then cured. Suitable carrier resinsinclude acrylic latex, epoxy, polyvinylchloride, ethylenevinylchloride,polyurethane, polyvinylacetate, acrylonitrile rubber, melamine andco-polymers of these compounds. The phosphorescent coated fabric canthen be utilized with both thermoplastic resins (which can be melted andreshaped with heat after curing) and thermosetting resins (which cannotbe melted and reshaped with heat after curing) to make FRP (fiberglassreinforced plastic) products. This approach utilizing a phosphorescentfabric was taken for two reasons: 1) previous attempts to add aphosphorescent material directly to a resin system have beenunsuccessful, mainly due to the settling away of high densityphosphorescent material from the surface of the final article; and 2)the overall relative opacity of the resin mixtures due to shielding byfillers, which prevents the phosphorescent materials from being chargedwhich, in turn, prevents the glow from being visible.

[0020] The method of coating the fabric with a phosphorescent utilizedby Vockel, Jr. et al. has still left a need for polyester thermosetresin systems in which the phosphorescent pigments do not settle duringstorage and use and a need for polyester resin systems with suitabletransparency and/or translucency characteristics for better utilizationof phosphorescent particles. Such thermosetting luminescent resins wouldbe extremely useful as thermosetting resins have properties making themsuitable for large items such as boats and spas as well as smalleritems. In addition to applications where thermosetting laminating resinsare used with fibrous reinforcements, there is a need for improvedluminescent thermosetting resins, methods and products in both gel coatapplications and casting and molding applications where reinforcingfabrics are not utilized.

[0021] Unsaturated polyesters are well known in the art and have beenextensively studied and described. Fiberglass reinforced plastic (FRP)is a material in which fibrous materials (including fibers other thanglass) are combined with resinous materials, such as thermosetting orthermoplastic polymer resins, to make an article that is stronger thanthe resin itself. FRP processes are utilized to produce numerous goodssuch as furniture, swimming pools, baths and spas, boats, automotiveproducts, aerospace products, sporting goods and toys.

[0022] Thermosetting resins encompass a wide range of materialsincluding, for example, polyesters, vinyl esters and epoxies. Infabricating a thermoset polyester FRP article, various processes areutilized in which the fiber reinforcements are saturated or wet-out witha liquid thermosetting resin and shaped either manually or mechanicallyinto the form of the finished article. Once formed, the shape is allowedto cure via polymerization of the thermosetting resin. A gel coat mayoptionally be applied in open mold processes prior to the FRP process.Thermoset molding and casting processes may be utilized to formnon-fabric reinforced articles, typically utilizing milled and/or shortfiber reinforcement.

[0023] Gel coats were introduced when thermosetting polyester resinswere first being introduced for use with fiberglass or other fiberreinforcements. It was noticed in molded parts that the surfaces showeda distinct three-dimensional fiber pattern caused by shrinking of theresin away from the glass fibers during curing. Since these early partswere utilized almost exclusively for aircraft, this could not betolerated for aerodynamic and aesthetic reasons. A remedy was soondeveloped in the use of gel coats, which today are utilized on thesurface of thermosetting polyester plastics to produce a decorative,protective, glossy surface which requires little or no subsequentfinishing. Resin and glass fiber reinforcement is applied directly overthe gel coat by hand lay-up or spray-up techniques to produce a plasticin which the gel coat coating is an integral part of the composite. Thegel coat serves to suppress glass-fiber pattern, eliminating“alligatoring” and crazing of surface resins, eliminating chalking afteroutdoor weathering, filling pin-holes and rendering the surfaceresilient, tough and abrasion and impact resistant (without sacrifice ofwater resistance) so that it can be readily cleaned or buffed to a highgloss. The gel coat surface further acts as a barrier againstultraviolet radiation which would otherwise degrade the glass fiberlaminate within the FRP, reduces or eliminates blistering of substratein high humidity, eliminates the possibility of “weeping” of glass fiberin the presence of water and so on. Gel coats are used extensively forsuch items as shower stalls and bath tubs, outer surfaces of boats,campers, automotive bodies, swimming pools and a host of other parts andsurfaces where a smooth, hard, tough and colored surface is a necessity.

[0024] A large number of photocurable unsaturated polyester resinsutilizing various photocatalyst polymerization catalysts are known tothe art and are particularly used in the preparation of surface coatingsand in the preparation of fiber reinforced composites such as prepregs.Photocurable resins and photocatalysts include those disclosed in U.S.Pat. Nos. 4,017,652 (1977) to Gruber; 4,116,788 (1978) to Schmitt etal.; 4,265,723 (1981) to Hesse et al.; 5,554,666 (1996) to Livesay; and5,554,667 to Smith et al.

[0025] As has been mentioned, one problem with utilizing phosphorescentpigments (which may have a specific gravity of 3.5 to 4 or more) inpolymer resins is the tendency of the phosphorescent pigment to settleduring blending operations and storage, particularly the larger sizeparticles. Usually known luminescent polymers must be blended andutilized immediately, often with air equipment to keep thephosphorescent particles in suspension. This is also true ofthermosetting laminating and casting resins, where typically thephosphorescent particle falls out of suspension and cannot be sprayed orconveniently worked. Thus, there is a particular need for polyesterthermoset methods and products which keep the phosphorescent particlesin suspension not only during blending and application, but also duringstorage over the useful life of the luminescent polymer.

[0026] An additional problem arises when attempting to utilize aphosphorescent pigment with polyester gel coats. If a phosphorescentparticle such as an activated zinc sulfide is added to a gel coat,typically the phosphorescent particles separate out and the mixtureovercongeals (similar to adding too much flour to water). An unmet need,therefore, remains apparent for phosphorescent polyester gel coats aswell as moldable resins, which has not been provided by the prior art.

[0027] Even more useful would be a photocurable polyester base resineasily adapted for gel coating applications, laminating applications,casting applications and various molding applications such as injectionor blow molding. Typically gel coats are unsuitable as laminating orcasting resins, easily crumbling in the hands if molded in thick layers;laminating and casting resins have surface finish problems requiring theuse of a gel coat. The usual laminating resins typically cannot be usedin casting applications as layers more than 7-10 mm thick will overheatduring cure and fracture due to the intrinsic heat buildup. Aphotocurable phosphorescent thermosetting polyester base resin easilyadapted to both gel coat applications and the various molding,laminating and casting processes would therefore be particularly useful.

[0028] Electroluminescent devices were evidently first proposed byDestrau in 1947. Such a lamp may comprise a sheet of glass or plasticwith a conductive layer which acts as a first electrode, anelectroluminescent layer comprising phosphor in a binder and aconductive sheet on the other side of the electroluminescent layer whichserves as a second electrode. When a voltage is applied across the twoelectrodes, the phosphor will emit light.

[0029] For example, U.S. Pat. No. 4,916,360 (1990) to Mikami et al.discloses a thin film electroluminescent device that comprises anelectroluminescent film made with zinc sulfide serving as its hostmaterial and doped with a rare earth element to provide luminescentcenters, insulating layers sandwiching the film and a pair of electrodeson the outer surface of the insulating layers. The EL film preferablyhas a ratio of sulfur to zinc atoms (S/Zn) of about 1.02≦S/Zn≦1.13,adapted to achieve an increased excitation efficiency at the luminescentcenters to exhibit improved luminescent brightness. Rare earth elementshaving atomic number 59 to 69 (Pr to Tm) are suitable for doping, amongwhich terbium, samarium, europium and praseodymium are desirable andselected in accordance with the desired luminescence color. The film isdoped with the rare earth elements in an amount of 0.5 to 3 atom %. U.S.Pat. No. 3,740,616 (1973) to Suzuki et al. discloses electricallyluminescent display devices which can be controlled to displaycharacters or patterns. The display devices employ plural-gappedelectrodes and multiple layers including an electrically luminescentlayer. The electrically luminescent layers disclosed include acomposition of zinc sulfide powder activated with copper and aluminumand a plastic binder such as urea resin, zinc sulfide powder activatedwith copper or manganese in thin film form, cadmium sulfide or siliconcarbide luminescent materials and ZnCdS:Ag luminescent material. Aninsulating layer such as polyester film or barium titanate and a plasticbinder which is white in color may be utilized and reflects theluminescence emitted from the electrically luminescent layer, thusintensifying the light output. U.S. Pat. No. 4,665,342 (1987) to Topp etal. discloses polymer luminescent displays formed of a matrix ofindividual light emitting elements adapted for excitation from a voltagesupply. The electroluminescent displays can be manufactured usingprinted circuit and screen printing techniques. The matrix is formed ona substrate and each of the light-emitting elements comprises a firstelectrical conductor overlying the substrate, a dielectric withrelatively high dielectric constant overlying the first electricalconductor, a light-emitting phosphor embedded in a polymer binderoverlying the dielectric, and a second light transmissive electricalconductor such as indium oxide or indium oxide/silver polymer overlyingthe phosphor and defining a window for enabling viewing of theelectrically excited phosphor. A polymer dielectric with a relativelylow dielectric constant separates each of the individual light-emittingelements from each other and alleviates cross-talk between theindividual light-emitting elements. These examples point out acontinuing need for improved phosphorescent polymers forelectroluminescent applications.

[0030] In summary, there remain various needs and unsolved problemswhich must be overcome before thermoset polyester resins can be mosteffectively utilized with the various phosphorescent particles.Effective photocurable thermoset resins must be water-resistant, protectUV sensitive phosphorescent pigments and provide a means for keepingheavy phosphorescent particles in suspension during storage and use.Such thermoset resins should have acceptable optical properties for usewith phosphorescent pigments. An ideal thermoset phosphorescentpolyester resin could be used or easily modified for use as a gel coat,laminating resin, casting resin or moldable resin and would haveexcellent photoluminescent, thermoluminescent and electroluminescentproperties.

BRIEF SUMMARY OF THE INVENTION

[0031] In view of the foregoing disadvantages inherent in the knowntypes of luminescent materials, the present invention provides improvedphotocurable luminescent thermosetting polyester blends.

[0032] Photocurable photoluminescent, thermoluminescent andelectroluminescent phosphorescent resins useful as a base for gelcoated, laminated, cast and molded articles are provided. Thephotocurable luminescent resins are thermosetting polyester resins withproperties intermediate between those of typical polyester gel coats,laminating resins and casting resins, containing suspending fillers andphosphorescent pigments. The photocurable luminescent polymers haveimproved luminescent properties and improved phosphor-suspendingproperties for ease of storage and use. Polymerization may be initiatedby natural sun light or by an ultraviolet light source.

[0033] The photocurable luminescent polymer resins may be convenientlyfabricated by mixing various thermoset polyester gel coat resins,laminating resins and casting resins, sufficient suspending filler ormixture of suspending fillers, a phosphorescent pigment and aphotocatalyst. UV stabilizers (inhibitors, antioxidants, etc.) arepreferably added to protect polymers and any phosphorescent pigmentssubject to “greying” when such pigments are utilized.

[0034] Preferred unsaturated polyester resins in the present inventionincorporate maleic and fumaric unsaturated components, orthophthalic andisophthalic aromatic components or substituted derivatives and a glycolor mixtures of glycols (such as neopentyl glycol, propylene glycol,ethylene glycol, diethylene glycol, dipropylene glycol) with styrenemonomer. Useful suspending fillers include silica, glass microspheresand various flake, fiber and crystalline fillers. Preferredphosphorescent pigments include multiply activated zinc sulfidephosphors, multiply activated metal aluminate oxide phosphors such asalkaline earth aluminate oxides and mixtures of these phosphors. Thephotocurable luminescent polymer base resin may be made flexible by theaddition of orthophthalic and/or isophthalic flexible resins and fireretardant through the use of halogen-substituted derivatives and variousadditives. The luminescent polymer base resin can be easily modified foruse as a gel coat, a laminating resin for FRP products, a casting resinor a moldable resin.

[0035] The improved photocurable luminescent polymers shows unexpectedluminescent and polymer properties. Such luminescent properties includea combination of bright and extremely long glow, rapid recharging ofphotoluminescent properties after exposure to light and a very strongthermoluminescence which can be activated by heat sources such as bodyheat, motor heat, brake heat and hot water. Unusual thermoset polymerproperties include suitability, ready adaptability and ease of use as agel coat, a laminating resin, a casting resin and a moldable resin aswell as an ability to keep heavy phosphorescent particles in suspensionduring extended storage and use.

[0036] Accordingly, it is an object of the present invention to providephotocurable luminescent thermosetting polymers with both a brightinitial luminescence and a long-lasting luminescence.

[0037] It is another object of the present invention to provide aphotocurable luminescent polyester resin suitable for use as a gel coat.

[0038] It is another object of the present invention to providephotocurable luminescent polymers providing excellent water-resistanceand UV protection to sensitive phosphorescent pigments.

[0039] It is another object of the present invention to provide aphotocurable luminescent thermosetting polyester resin suitable for usein laminating applications.

[0040] It is another object of the present invention to provide aphotocurable luminescent thermosetting polyester resin suitable for usein molding applications.

[0041] It is another object of the present invention to provide aphotocurable luminescent thermosetting polyester resin suitable for usein casting applications.

[0042] It is another object of the present invention to providephotocurable luminescent polyester gel coats and moldable resinssuitable for long term storage and use.

[0043] It is another object of the invention to provide photocurablephotoluminescent polymers which strongly thermoluminesce when exposed toheat.

[0044] It is another object of the invention to provide improvedmixtures of phosphors, particularly activated zinc sulfide and metalaluminate oxide phosphors, suitable for use in luminescent polymers.

[0045] It is another object of the present invention to providephotocurable electroluminescent plastics.

[0046] A further object of the invention is to provide a method forefficient production of photocurable thermosetting phosphorescent resinmaterials possessing such excellent phosphorescent qualities as lightdensity and light fastness or afterglow combined with excellent polymerresin properties in suspending, protecting and utilizing phosphorescentpigments.

[0047] The photocurable luminescent resins disclosed herein have beenfound to achieve these objects and advantages. Other objects andadvantages of this invention will become apparent from the followingdescription and appended claims.

DETAILED DESCRIPTION OF THE INVENTION

[0048] Before explaining the preferred embodiments of the presentinvention in detail, it is to be understood that the invention is notlimited in its application to the particular details disclosed. Nolimitation with respect to the specific embodiments disclosed isintended or should be inferred. Although the present invention has beendescribed with reference to preferred embodiments, numerousmodifications and variations will be apparent to one skilled in the art.These modifications can be made and still the result will come withinthe scope of the invention. The terminology used herein is for thepurpose of description and not of limitation.

[0049] In order to better illustrate the luminescent gel coats andmoldable resins disclosed here, the following definitions will beutilized.

[0050] Although the popular use of the word “phosphorescence” impliesany kind of cold light, this term will be restricted here to the lastingluminescence which results from exposure of a substance to visible orultraviolet radiation—what is more properly designatedphotoluminescence. An important characteristic of the phosphorescentsubstances is that no permanent chemical change need result from theexposure to light, thus distinguishing it from chemiluminescence.

[0051] The term “thermoluminescence,” because of its early discovery andlong usage, has been retained for the emission of light on heating asubstance to relative low temperatures (far below the point at whichincandescence begins). The word implies that heat energy excites theluminescence, and indeed the present invention acts as if heat energyexcites luminescence, but theoretical considerations suggest heat merelyliberates energy in the form of luminescence, the energy havingpreviously been absorbed from light and stored in the material. The moreappropriate term of “thermostimulation” might be applied to conform withthe modern explanation of excitation of electrons by the rise intemperature, whose transitions result in the emission of light. Here“thermoluminescence” and “thermostimulation” will be usedinterchangeably.

[0052] “Electroluminescence” is usually applied to the light resultingfrom flow of current through partially evacuated tubes of gas. However,the phenomenon of electroluminescence also includes, and will be hereutilized to describe, the excitation of a luminous sheet ofphosphorescent material by an electric current.

[0053] The term “unsaturated polyester resin” and “unsaturated polyestergel coat resin” as used herein is intended to encompass thermosettingpolyesters made by condensing ethylenically unsaturated dicarboxylicacids or anhydrides or mixtures thereof with a dihydric alcohol ormixtures of dihydric alcohols. The term “polymerizable vinylidenemonomer” as used herein is intended to encompass vinyl monomers that arepolymerizable with the above-described polyesters.

[0054] The need for a useful renewable light source is made apparent bythe list of applications for the luminescent polymer blends of thepresent invention. A partial list of such applications would include:signs (such as warning, exit, advertising, building, directional,accident prevention and street signs); underground or building emergencyillumination (including buildings and corridors, airplanes, mineshafts,subways and underground stations, air-raid shelters and hangars); streetcrosswalk, curb and lane markers; light panels; stairwells and stairtread illumination (especially fire stairs and edges of steps); vehiclemarkings (including cars, trucks, aircraft, boats, bicycles, trailers,life rafts, hand gliders and helium and hot air balloons); hard hats andsafety helmets; safety clothing; barriers and nets for oil spills;outdoor clothing (both urban and wilderness); prisoner's uniforms (adeterrent to night escapes); watch faces, gauges, dials and panels; skisand skateboards; ropes and ramps for water-skiing; parachutes andparasails; marine buoys; camping equipment; fishing equipment (poles,lures and nets); house numbers; safety barricades; agricultural fencingand gate markers; dog, cat and animal collars, harnesses and markers;bush and ski trail markers; telephone and electrical line markers;license plates and emergency vehicle ID and markings; military anddefense force applications; fascia and outlines for ignition switches,locks and light switches; smoke detectors including directionalmarkings; musical instruments; night lights; dishes; figurines; insectstrips and traps; artificial grass; marine and outdoor carpets;alternatives to reflective markers and tapes; toys; jewelry; mannequins(green and red phosphorescent pigments may be combined to give pinkishskintones); special effects; novelties; etc.

[0055] Emergency lighting must operate at all times and in adverseconditions and atmospheres (loss of power, fire, smoke, etc.) and hencecreates special difficulties particularly suited to cold light renewableluminescence.

[0056] The luminescent polymers disclosed herein are also very usefulfor coating solar cells, serving to increase output on cloudy days.

[0057] Another novel use is coating the reflectors of headlights andother lamps with the luminescent gel coat (which also has goodreflective properties). This helps to create a uniform and increasedbeam of light with no shadows. In combined parking/headlight lamps, itserves to create illumination from the entire reflector when only onelight is activated. Taillight lenses may contain luminescent areas whichwill glow even if the taillight is burned out.

[0058] One of the more novel uses for the photoluminescent materialsdisclosed herein are as an aid to bacterial control in hospitals As afavorite hiding place for bacteria in operating rooms is the darkenedareas on the backside of the light reflectors above the operating table(where they tend to fall off onto the patient when disturbed by aircurrents), coating the backside of the reflector will illuminate thearea, making it less hospitable for the light-shy bacteria.

[0059] “Black lights” (safe UV lights) are particularly suited forenergizing the luminescent polyesters disclosed herein. Black lightbulbs coated with the polyesters are particularly useful, as theluminescent gel coats will glow brightly for extended periods afterrelatively short illumination.

[0060] The luminescent gel coat is also particularly suited forprecision molding processes in that the thickness of the gel coat can bemore easily measured as thin areas are relatively darker.

[0061] Luminescent base material for circuit boards and computer chipsallows illumination of chips and components for alignment, inspectionand diagnostic purposes. “Hot spots” in the chips, parts or connectionswill cause the luminescent polyester to glow more brightly, particularlyuseful for design analysis and predicting failure of components.

[0062] The luminescent polymers described herein are also particularlyuseful in certain applications due to the thermoluminescent properties.Thus, for example, clothing and helmets may be activated by body heat,wheels and hubcaps of automotive vehicles may be activated by brakeheat, motor covers of marine vehicles and hoods and fenders ofautomotive vehicles may be activated by engine heat, spas, showers,bathtubs and hottubs may be activated by water heat and other objectsmay be activated via hot air or liquids.

[0063] Novel special effect uses include “liquid writing” on theluminescent polyesters utilizing laser beams or pointers. Interestingeffects are further available by coating fiber optic material with thephotoluminescent polymers described below. Such photoluminescentpolyester coated fiber optics are also useful for signs and directionalmarkers. Heat activated thermostimulation of a photoluminescent articlemakes the heated areas glow much brighter in chosen designs or writing;hot water works admirably, as will other hot liquids, gases or heatingelements.

[0064] The luminescent polymer also is also useful forelectroluminescent lighting, the luminescent polymer being coated with ametallic and a transparent conductor. Signs may be powered by smallbatteries in areas where electrical current is not available oreconomical.

[0065] Electroluminescent devices such as luminous capacitors utilizingelectroluminescent polymers (composites comprising electroluminescentpigment particles in a polymeric matrix) may be constructed as follows:a conductive substrate (metal, glass with a conductive layer, conductivepolymers) is coated with a thin layer of a phosphorescent pigmentembedded in a binder with a high dielectric constant (such as theluminous polymers described herein). Typically a much smaller percentageof luminescent phosphor (<1% by weight) is utilized in theelectroluminescent embodiments as compared to the photoluminescentembodiments. A smaller percentage of long-life phosphor is desirable inelectroluminescent applications so that the light will fade when poweris interrupted. Alternatively, short life phosphors may be employed, inlarger amounts if desired. Layers can be applied by any of the knownmethods: spray, curtain coating, screen printing or spread coating, ormore exotic methods such as vacuum deposition, ion plating, sputteringand chemical vapor deposition (these and other methods known to thoseskilled in the art). Plastic or ceramic compounds with high dielectricconstants are used as binders. The optimum layer thickness depends onthe voltages and the frequencies at which the luminous capacitor is tofunction.

[0066] It is known that unconjugated portions of a polymer show arelatively high quantum efficiency (photons out per excited state, i.e.,photons out per photon absorbed for photoluminescence and photons outper electron injected into the structure for electroluminescence) forthe radiative decay of singlet excitons. See, for example, U.S. Pat. No.5,401,827 (1995) to Holmes. However, the efficiencies and efficacy ofluminescent materials, particularly polymer containing materials, arenot totally explicable by contemporary theoretical models. Thereforethere is no presentation herein of a precise explanation as to why thepresent invention may exhibit higher efficiencies includingphotoluminescent brightness and length of afterglow andthermoluminescence as compared to known luminescent materials.

[0067] In general, a long life phosphor is preferable forphotoluminescent and thermoluminescent applications of the presentinvention as it may become necessary to overload the plastics withadditives otherwise. Mixtures can occasionally be useful, particularlythat of a phosphor with a very bright initial illumination and aphosphor with an extended afterglow or a mixture of slow and quickcharging phosphors. For use in electroluminescent applications, greatlyreduced quantities are generally preferred so the luminescence willquickly fade when electrical stimulation ceases.

[0068] Various considerations are taken into account when choosing aphosphor or mixture of phosphors for use in various applications.Alkaline earth metal aluminate oxides are preferred outdoor applicationsand high intensity light applications due to their brighter initialafterglow and longer afterglow. Zinc sulfide phosphors are preferred inconditions of low light illumination for charging. As the alkaline oxidealuminate phosphors are much more expensive than the zinc sulfidephosphors, the zinc sulfide phosphors may be preferable in manyapplications (such as lower-priced lines and novelties) for economicreasons. Mixtures of zinc sulfide and alkaline earth aluminate phosphorsare most useful for objects that may receive both outdoor light andindoor illumination of varying intensities (such as bicycles, clothing,etc.). Mixtures are also most useful for short excitation situations,the zinc sulfide phosphor attaining bright luminescence and saturatingcharging more quickly than the alkaline earth aluminate oxide phosphors.The sulfide phosphors giving various colors are useful for theirparticular color and for blending with the yellow-green of copperactivated zinc sulfide and alkaline earth aluminates, but length ofafterglow tends to be shorter. Short life phosphors of other types knownto the art may be preferred for certain electroluminescent applications,particularly in applications where it is important or desired that thelight “turn off” rapidly after electrical stimulation ceases.

[0069] Although the luminous polyesters disclosed herein can hold 50% ormore of phosphorescent pigment, amounts of <1%-20% are generallypreferred with 10%-20% being preferred for photoluminescent andthermoluminescent applications and <1%-2% being preferred forelectroluminescent applications. Preferred zinc sulfide phosphors mayoptionally include selenium and silicon. The zinc sulfide phosphors arepreferably activated by copper and more preferably additionallyactivated by a metal element or plurality of metals selected from thegroup consisting of aluminum, silver, gold, magnesium, manganese,gallium, indium, scandium, iron, calcium and/or lead, by a rare earth orrare earth elements such as cerium, terbium, europium, gadolinium,samarium and/or praseodymium, by halogens, by silicon and/or seleniumand by mixtures these elements, particularly by mixtures of metals andrare earths with or without silicon and selenium. Zinc calcium sulfidephosphors and mixtures of zinc sulfide phosphor with calcium sulfidephosphor are also preferred. Preferred metal aluminate oxide phosphorsare alkaline earth metal aluminate oxide phosphors such as strontiumaluminum oxide, calcium aluminum oxide, barium aluminum oxide ormixtures thereof, preferably activated with europium and co-activatedwith an element such as lanthanum, cerium, praseodymium, neodymium,samarium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium,lutetium, the metals tin and/or bismuth or mixtures thereof. Thepreferred alkaline earth metal aluminate oxides may optionallyadditionally contain magnesium aluminum oxide. Examples of suitablephosphorescent pigments include multiply activated zinc sulfide such asLUMILUX® ZnS:Cu, available from Hoechst or AlliedSignal of Australia,UMC Phosphorescent pigments (zinc sulfide and mixtures with othersulfides), available from United Mineral & Chemical Corp., USA,rare-earth activated alkaline earth aluminate oxides such as LUMILUX®Green-SN long afterglowing pigments available from AlliedSignal ofAustralia, and LUMINOVA® strontium aluminate oxide pigments availablefrom United Mineral and Chemical Corp., USA, and mixtures of thesephosphors.

[0070] Suitable sources of excitation for the photoluminescent polymersdisclosed herein include daylight, UV light and most forms of artificiallight. In general, the wider the spectrum of the energizing light, thelonger the afterglow of the photoluminescent plastics. White light richin UV is very suitable. Red light or yellow light from a sodium vaporlamp is generally less suitable, as are filament bulbs for alkalineearth aluminates in general. Certain luminescent polymers describedherein can also be energized or stimulated by electromagnetics andfriction (static charges).

[0071] The unsaturated polyesters of use in the present invention arethe reaction products of polycarboxylic acids or anhydrides and one ormore polyhydric alcohols dissolved in a crosslinking monomer containingan inhibitor to prevent crosslinking until the resin is used by thefabricator. The unsaturated polyester is the condensation product of oneor more unsaturated dicarboxylic acids or anhydrides, one or morearomatic dicarboxylic acids or anhydrides and one or more polyhydricalcohols in combination with a polymerizable vinylidene monomer. One ormore of the components of the polyester must be ethylenicallyunsaturated, preferably a polycarboxylic acid component.

[0072] Typical unsaturated acids include dicarboxylic acids andanhydrides such as maleic anhydride, maleic acid, fumaric acid,methacrylic acid, acrylic acid, itaconic acid and citraconic acid.Maleic anhydride is the most economic derivative, although fumaric acidcan be substituted, yielding resins with the same properties but somesubtle structural differences. In most commercial formulations, thereactivity of the polyester polymer is derived primarily from the maleicanhydride component. Maleate and fumarate based resins utilizing maleicanhydride, fumaric acid or maleic acid or mixtures thereof are preferredin the present invention. Acrylic acid and methacrylic acid modifiedpolyester resins also find use.

[0073] The degree of unsaturation is varied by including a saturateddibasic acid (which includes aromatic acids insofar as polyesters areconcerned) such as phthalic anhydride, isophthalic acid, phthalic acid,chlorendic anhydride, tetrabromophthalic anhydride, tetrachlorophthalicanhydride, tetrahydrophthalic acid and anhydride, adipic acid, succinicacid, suberic acid, sebacic acid, azelaic acid, terephthalic acid, etc.Orthophthalic (derived from phthalic anhydride or phthalic acid) andisophthalic (derived from isophthalic acid) based polyester resins andtheir substituted and halogenated derivatives are particularly preferredin the practice of the present invention. DCPD modified phthalic and/orisophthalic resins may also find use.

[0074] Typical polyhydric alcohols include glycols, such as propyleneglycol, ethylene glycol, neopentyl glycol, diethylene glycol,dipropylene glycol, 1,4-butanediol, dibromoneopentyl glycol,2,2,4-trimethyl-1,3-pentanediol, 1,3-butanediol, 1,5-pentanediol,1,3-propanediol, hexylene glycol, triethylene glycol, tetraethyleneglycol, dicyclopentadiene hydroxyl adducts etc.; propylene oxide; triolssuch as trimethylol ethane, trimethylol propane, trimethylol hexane, andhexane triol; Bisphenol A ethers and Bisphenol A adducts (such asbisphenol dipropoxy ether and the adduct of Bisphenol A with ethyleneoxide), hydrogenated Bisphenol A and brominated bisphenols; etc. Aglycol or mixtures of glycols are usually preferred in the presentinvention, particularly those glycol based polyesters that are based onneopentyl glycol or mixtures containing neopentyl glycol (such asneopentyl glycol and one or more of propylene glycol, ethylene glycol,diethylene glycol, dipropylene glycol, dibromoneopentyl glycol,bisphenol dipropoxy ether, 2,2,4-trimethylpentane-1,3-diol,tetrabromobisphenol dipropoxy ether, 1,4-butanediol, Bisphenol Aadducts, hydrogenated Bisphenol A and DCPD hydroxyl adducts).

[0075] The ethylenically unsaturated polyester is usually a semi-rigidpolyester or flexible polyester although mixtures of these can be usedwith rigid polyesters. The preferred polyesters form copolymerizateswith vinylidene monomers. The preferred vinyl monomer is styrene.Styrene when compared with other commercial monomers usually offersequivalent properties at much lower cost; higher boiling, less volatilemonomers (such as vinyl toluene) may offer advantages in reducingemissions.. Certain monomers enhance specific properties, for examplediallyl phthalate and triallyl cyanurate extend the thermal durabilityrequired in certain electrical components. Monomers including vinylaromatics such as vinyl toluene, α-methylstyrene, divinylbenzene,p-t-butylstyrene, o-chlorostyrene and dichorostyrene, the alkyl estersof alpha, beta-ethylenically unsaturated monocarboxylic acids such asmethyl methacrylate, methylacrylate, ethylacrylate and2-ethylhexylacrylate, and the vinyl esters such as vinyl acetate andvinyl proprionate are also of utility, alone, in combinations, or incombination with styrene. The vinyl esters are generally less suitablefor the practice of the present invention. Preferably, the ethylenicallyunsaturated polyesters comprise from about 30 to 80 percent of thepolymerizable resin-forming components, with the remaining 20 to 70percent being composed of the crosslinking vinylidene monomers. Controlof the amount of styrene or monomer is particularly useful in obtaininghigh gloss surface finishes.

[0076] Exposure to heat or light may result in uncontrolledcross-linking and an increase in viscosity; therefore inhibitors(free-radical inhibitors) such as hydroquinone, toluhydroquinone,parabenzoquinone and/or tertiary butyl catechol are typically includedin resin formulations to suppress oxygen-initiated free-radicalformation and prevent reaction prior to addition of the catalyst.

[0077] Weathering resistance is obtained by using neopentyl glycol,methyl methacrylate and UV stabilizers (discussed below). Aromaticderivatives such as isophthalic acid, terephthalic acid or diols derivedfrom Bisphenol A provide a higher degree of hardness, rigidity andenhanced thermal characteristics. Aliphatic constituents such as adipicacid, 1,4-butanediol and diethylene glycol yield soft, pliable products.Property modification is influenced by the number of methylene oroxyethylene units separating the reactive functionality. Monofunctionalchain terminators such as benzoic acid or dicyclopentadiene (DCPD) maybe employed to develop certain characteristics. Other characteristicsare derived from reactive halogenated compounds which impart flameresistance.

[0078] Highly branched aliphatic or substituted aromatic derivativesintroduce steric effects around the double bond, which reduces itsability to cross-link with styrene or other monomers;2,2,4-trimethyl-1,3-pentanediol is particularly notable in this respect.α-Methylstyrene is similarly influenced by the pendent methyl groupingon the double-bond carbon, which impedes its reaction rate during thecross-linking with fumarate groups.

[0079] Usually, the longer the chain length of the glycol or unsaturateddicarboxylic acid components making up the polyester, the more flexiblethe polyester. Aromatic components, particularly phthalic acid, are notas effective as long-chain saturated aliphatics in lowering the elasticmodulus of the copolymer. Synthetic elastomers also find some use inflexible polyesters.

[0080] Gel coats and similar formulations are also variously referred toas gelcoats, flow coats, flowcoats and glazes (glazes typically refer toclear gel coats used to improve the stain resistance, gloss, and depthof coating when applied over cultured marble or cast products). Gelcoats utilized in swimming pools are typically nonporous gel coats. Flowcoats typically include additional wax and styrene and have superiorleveling properties to hide imperfections on the bare fiberglass side ofmolded products. Tooling gel coats, usually neopentyl glycol based, aredesigned to meet the exacting requirements of gel coats which are usedto manufacture molds. Gel coats (and other polymer resins) are oftenavailable in two grades, a summer grade for higher temperatures and awinter grade with promoter materials which will raise the temperature ofthe curing material after the addition of an appropriate catalyst. Gelcoat resins based on neopentyl glycol or a mixture of neopentyl glycolwith other glycols are preferred in the practice of the presentinvention.

[0081] The usual gel coat is a polyester resin, often heavily filledwith a mineral filler (and pigment if present), that shows very littleshrinkage because of its high filler-to-resin ratio. Formulationstypically include various additives and catalysts are added just beforeapplication. Gel coats typically result in a hard, smooth coating250-750 μm thick when properly applied and cured. Since the gel coatcontains no glass fiber reinforcement, its surface retains a glossyappearance and does not erode to expose glass fibers as in noncoated FRPproducts.

[0082] A typical polyester gel coat formulation might contain thefollowing component materials:

[0083] Resin: A low viscosity (500-1000 cps) resin is used so it can beeasily filled and will allow entrapped air to escape. Usually ahigh-impact grade is preferred to insure freedom from chipping caused byimpact or thermal stresses. Concentration in the complete formulation istypically 25-95% by weight.

[0084] Fillers: The most widely used fillers are calcium carbonate (finesynthetic high purity grades are used for high-viscosity, nonsag coats),hydrated aluminum silicate and other silicates, nepheline syenite,feldspar, carbides, oxides, metal powders and carbon, depending on theparticular physical, chemical, or electrical properties desired. Thefillers are used primarily to reduce the resin shrinkage, lower theexotherm, increase the hardness, increase the thermal conductivity anddimensional stability, increase the fire retardance, or change thedensity and opacity of the resin. The filler concentrations may rangefrom 5-75% by weight.

[0085] Thixotropic Agents: Colloidal silica or fumed silica andmagnesium aluminum silicate clays (such as bentonite) are used asthixotropic modifiers to prevent sagging and running of the gel coatwhen applied to vertical surfaces and void-free dense surfaces. They arealso used to minimize filler settling and increase pigment efficiency.They are used in concentrations of 2-15% by weight. Other knownthixotropic agents include hydrogenated castor oil and aliphatic acidamides. As is well known in the art, the thixotropic characteristics ofgel coats need to be precisely controlled in view of the thickness ofthe deposited film and the tendency of such films to sag. The gel coatshould be uniformly thixotropic so as to eliminate dripping when appliedto vertical surfaces and void-free dense surfaces. Gel coat formulationstypically contain accelerators, as extension of gel time can impair thecure of the gel coat in the allotted time, with subsequent applicationof the resin laminate causing the gel coat to swell and wrinkle. Specialattention must be paid to gel-time drift caused by thixotropic agentssuch as fumed silica.

[0086] Pigments: Pigments are dispersed into the resin to act ascoloring agents. They are used in concentrations of 0-10% by weight.

[0087] Solvents: Solvents such as acetone are added to the formulationto thin the material to spraying consistency. The minimum amount ofsolvent (or preferably no solvent) is used since its use can result inattack on the mold release, resulting in sticking parts, poor surfaces,etc.

[0088] Other useful components include inhibitors, cure accelerators,leveling agents, defoaming agents and adhesives.

[0089] Gel coats, including those luminescent gel coats of the presentinvention, are typically formulated to provide minimal draining onvertical surfaces when applied at wet film (surface) thicknesses ofapproximately 0.50-0.76 mm. As much as 30% shrinkage may occur from wetfilm to cured film thickness.

[0090] Typically catalyzed gel coats are applied to the release-coatedmold surface or other surface by spray (the most common method), brush,roller coat or forced slush. The coat is allowed to gel and thereinforcing fiber and laminating resin are applied while the gel coat isstill tacky. If done correctly, the bond between the gel coat and thefiber-reinforced laminate will be an excellent one.

[0091] Gel coats usually must be used in conjunction with a laminatingresin, as gel coats utilized alone result in a material which is brittleand crumbles under stress. In this regard the present photocurableluminescent polymer is somewhat unique; the blending of gel coat,laminating and casting resins, combined with suspending fillers andmetallic phosphors results in a base formulation can be used or easilymodified for use as a gel coat resin, laminating resin, casting resin ormoldable resin.

[0092] Free radical polymerization of acrylic, vinyl and/or diene groupsrequires a source of free radicals, and further requires that thepolymer chain carrying radical be sufficiently reactive to add to anadditional group. The initial source of free radicals is usuallyprovided by a catalyst which, upon absorption of energy, producesradical pairs. At least one member of the radical pair is then capableof initiating chain growth.

[0093] In the case of thermal polymerizations, initiators are used whichabsorb thermal energy and then produce radical pairs. Examples of suchinitiators are peroxy esters and ketones such as methyl ethyl ketoneperoxide, diacyl peroxides such as benzoyl peroxide or dicumyl peroxide,hydroperoxides such as tertiary butyl hydroperoxide, and azo compoundssuch as α, α′-azobisisobutyronitrile. The free radicals serve asinitiators for free radical polymerization and or copolymerization ofmonomers, as curing agents for thermoset resins and as crosslinkingagents for elastomers.

[0094] In the case of photopolymerizations, initiators are used whichabsorb photons and thereby obtain energy to form radical pairs. In onetype of photoinitiation, the absorption of a photon produces a moleculeexcited to a higher energy level and the excited molecule then forms aradical pair. One or both members of the radical pair are then availableto initiate addition polymerization of acrylic, vinyl and/or dienegroups in the well-known manner. Because the photoinitiator does notrequire interaction with another compound to form free radicals, thereaction is termed unimolecular.

[0095] Free radicals necessary to photopolymerization also may beproduced by interaction of two compounds. Such reactions are thereforeclassed as bimolecular.

[0096] One type of bimolecular reaction is hydrogen abstraction. Here, aphotosensitizer, which is a good absorber of photons but which itself isa poor photoinitiator, absorbs photons to produce an excited molecule.The excited molecule then inter-reacts with a second compound to producefree radicals. One or both of the free radicals are available toinitiate addition polymerization of acrylic groups. In reactions of thehydrogen abstraction type, the photosensitizer is often destroyed by theprocess of generating free radicals.

[0097] Another type of bimolecular reaction is the energy donor type.Here a photosensitizer molecule absorbs a photon to produce an excitedmolecule. The excited molecule then transfers energy to a secondmolecule (monomer, polymer or added initiator) which produces radicalpairs. One or both free radicals are available to initiate additionpolymerization of acrylic groups. In reactions of the energy donor type,the photosensitizer serves to transfer energy and is not destroyed inthe process.

[0098] In bimolecular reactions of either the hydrogen abstraction typeor the energy donor type, the second compound with which the excitedphotosensitizer molecule interacts may, depending upon the specificidentity of the second compound, be an initiator or a monomer. In thelatter case, the monomer itself may be said to function as an initiator.

[0099] Preferred resins of the present invention are compounded with aphotocatalyst system, which, on exposure to UV-A light, initiates thegelling and curing process. Advantages of using a photocatalyst systemin the present invention include long shelf life and pot life (no gel orcure until exposed to UV light), a one-component system requiring nomixing or metering of catalyst prior to or during application isprovided, a quick and more complete cure utilizing sunlight or UV-Alights that is unaffected by typical shop temperatures, the ability touse smaller amounts of monomers and/or less volatile monomers) and anincrease in physical properties resulting from a more complete andfaster cure with less residual styrene or other monomer. Preferredphotocatalysts (photosensitizers and/or photoinitiators) for use in thepresent invention include those disclosed in U.S. Pat. Nos. 4,017,652(1977) to Gruber; 4,116,788 (1978) to Schmitt et al.; 4,265,723 (1981)to Hesse et al.; 5,554,666 (1996) to Livesay; and 5,166,007 (1992) and5,554,667 (1996) to Smith et al., all herein incorporated in theirentireties by reference.

[0100] Any suitable source that emits ultraviolet light (UV) lighthaving a wave length in the range of from about 1800 to about 4000Angstrom units, including both sunlight and artificial light, may beused in the practice of this invention. In order to initiate thepolymerization, it is sufficient to use the natural sun light a UVsource. However, depending on the field of application, specialultraviolet lamps will preferably be utilized, the emission of whichshould be within the range from 200 to 500 nm, particularly within therange from 320 to 400 nm, as this is also the case of the knownultraviolet polymerizations which are benzoin-activated. The time ofexposure to ultraviolet light and the intensity of the ultraviolet lightto which the composition is exposed may vary greatly. Generally theexposure to ultraviolet light should continue until the polymerizationis complete. A peroxide cocatalyst can optionally be utilized, but mustbe unpromoted and contain no cobalt or other transition metal salts.

[0101] U.S. Pat. No. 4,017,652 (1977) to Gruber discloses that oxygeninhibition of the photopolymerization of resins containing acrylicgroups may be substantially reduced by employing a photocatalyst systemcontaining (1) as a photosensitizer at least one aromatic ketone oraromatic aldehyde which has a triplet energy in the range of from about54 kilocalories per mole to about 72 kilocalories per mole and whichpromotes polymerization through bimolecular photochemical reactions ofthe energy donor type, and (2) as a photoinitiator at least one aromaticketone which generates a radical pair by way of unimolecular homolysisresulting from photoexcitation, at least one member of said radical pairbeing capable of initiating addition polymerization of acrylic groups.The catalyst system may be employed in ultraviolet light curable coatingcompositions containing resins having acrylic unsaturation and capableof being free radically addition polymerized by interaction with thephotocatalyst system upon exposure to ultraviolet light. The amount ofaromatic ketone or aromatic aldehyde photosensitizer present in thephotocatalyst system of the invention may vary widely, as may the amountof aromatic ketone photoinitiator present in the photocatalyst system.Examples of photosensitizers include benzophenone, benzil,3,4-benzofluorene, 1-naphthaldehyde, 1-acetylnaphthalene,2,3-butanedione, 1-benzoylnaphthalene, 9-acetylphenanthrene,3-acetylphenanthrene, 2-naphthaldehyde, 2-acetylnaphthalene,2-benzoylnaphthalene, 4-phenylbenzophenone, 4-phenylacetophenone,anthraquinone, thioxanthone, 3,4-methylenedioxyacetophenone,4-cyanobenzophenone, 4-benzoylpyridine, 2-benzoylpyridine,4,4′-dichlorobenzophenone, 4-trifluoromethylbenzophenone,3-methoxybenzophenone, 4-chlorobenzophenone, 3-chlorobenzophenone,3-benzoylpyridine, 4-methoxybenzophenone, 3,4-dimethylbenzophenone,4-methylbenzophenone, benzophenone, 2-methylbenzophenone,4,4′-dimethylbenzophenone, 2,5-dimethylbenzophenone,2,4-dimethylbenzophenone, 4-cyanoacetophenone, 4-fluorobenzophenone,o-benzoylbenzophenone, 4,4′-dimethoxybenzophenone, 4-acetylpyridine,3,4,5-trimethylacetophenone, 4-methoxybenzaldehyde,4-methylbenzaldehyde, 3,5-dimethylacetophenone, 4-bromoacetophenone,4-methoxyacetophenone, 3,4-dimethylacetophenone, benzaldehyde,triphenylmethylacetophenone, anthrone, 4-chloroacetophenone,4-trifluoromethylacetophenone, 2-chloroanthraquinone, ethylphenylglyoxylate, o-benzoylbenzoic acid, ethyl benzoylbenzoate,dibenzosuberone, o-benzoylbenzophenone, acrylyloxyethyl benzoylbenzoate,4-acrylyloxybenzophenone, 2-acrylyloxyethoxybenzophenone and mixtures ofthese photosensitizers. Examples of photoinitiators include ethylbenzoin ether, isopropyl benzoin ether, butyl benzoin ether, isobutylbenzoin ether, α, α-diethoxyacetophenone, α,α-diethoxy-α-phenylacetophenone, α, α-dimethoxy-α-phenylacetophenone,4,4′-dicarboethoxybenzoin ethyl ether, benzoin phenyl ether,α-methylbenzoin ethyl ether, α-methylolbenzoin methyl ether, α, α,α-trichloroacetophenone The preferred photoinitiators are isobutylbenzoin ether, mixtures of butyl isomers of butyl benzoin ether and α,α-diethoxyacetophenone. Mixtures of photoinitiators may be used, ifdesired.

[0102] U.S. Pat. No. 4,116,788 (1988) to Schmitt et al. discloses theaddition of an organic phosphite to a photocatalyst, substantiallyreducing the polymerization time of the resulting compositions. Theorganic phosphite photopolymerization activator can have solelyaliphatic or solely aromatic substituents and may also contain bothaliphatic and aromatic substituents in the same phosphite compound.Phosphite activators include dimethyl-phosphite, dioctyl-phosphite,diphenyl-phosphite, tri-i-octyl-phosphite, tri-stearyl-phosphite,tri-methyl-phosphite, tri-ethyl-phosphite, tri-i-propyl-phosphite,tris-allyl-phosphite, didecyl-phenyl-phosphite, tri-phenyl-phosphite,tris-4-nonyl-phenyl-phosphite and tris-4-chlorophenyl-phosphite. Asultraviolet initiators, benzoin or its derivatives can be used with thesubstances activated according to the invention, for example,benzoin-methylether, benzoin-ethylether, benzoin-i-propylether,benzoinbutylether, benzoin-trimethylsilylether, α-methylbenzoin,α-methyl-benzoin-methylether, α-methyl-benzoin-trimethylsilylether,α-(2-methoxy-carbonyl-ethyl)-benzoinmethylether,α-(2-cyanethyl)-benzoinmethylether orα-(2-carboxyethyl)-benzoinmethylether.

[0103] U.S. Pat. No. 4,265,723 (1981) to Hesse et al. discloses highlyreactive photocatalysts and photocurable compositions containingacylphosphine oxides of the formula or acylphosphonic acid esters as UVphotosensitizers. Examples of suitable phosphines aremethyldimethoxyphosphine, butyldimethoxyphosphine,phenyldimethoxyphosphine, toluyldimethoxyphosphine,phenyldiethoxyphosphine, toluyldiethoxyphosphine,phenyldiisopropoxyphosphine, tolyldiisopropoxyphosphine,phenyldibutoxyphosphine, tolyldibutoxyphosphine anddimethylmethoxyphosphine, dibutylmethoxyphosphine,dimethylbutoxyphosphine, diphenylmethoxyphosphine,diphenylethoxyphosphine, diphenylpropoxyphosphine,diphenylisopropoxyphosphine, diphenylbutoxyphosphine and similarcompounds. Particularly suitable UV sensitizers for unsaturatedpolyester resins are acyl-phenyl-phosphinic acid esters andacyl-diphenyl-phosphine oxides where acyl is derived from asecondary-substituted or tertiary-substituted aliphatic carboxylic acid,e.g. pivalic acid, 1-methylcyclohexanecarboxylic acid,norbornenecarboxylic acid, a mixture of α,α-dimethylalkanecarboxylicacids (Versatic® acid of 9 to 13 carbon atoms) or2-ethylhexanecarboxylic acid, or from a substituted aromatic carboxylicacid, e.g. p-methylbenzoic acid, o-methylbenzoic acid,2,4-dimethylbenzoic acid, p-tert.-butylbenzoic acid,2,4,5-trimethylbenzoic acid, p-methoxybenzoic acid orp-thiomethylbenzoic acid. Examples of such highly reactive UVsensitizers are methyl 2,6-dimethylbenzoyl-phenylphosphinate, methyl2,6-dimethoxybenzoyl-phenylphosphinate,2,6-dimethylbenzoyl-diphenylphosphine oxide,2,6-dimethoxybenzoyl-diphenylphosphine oxide, methyl2,4,6-trimethylbenzoyl-phenylphosphinate,2,4,6-trimethylbenzoyl-diphenylphosphine oxide,2,3,6-trimethylbenzoyl-diphenylphosphine oxide, methyl2,4,6-trimethylbenzoyl-tolylphosphinate,2,4,6-trimethoxybenzoyl-diphenylphosphine oxide, ethyl2,6-dichlorobenzoyl-phenylphosphinate,2,6-dichlorobenzoyl-diphenylphosphine oxide,2-chloro-6-methylthio-benzoyl-diphenylphosphine oxide,2,6-dimethylthio-benzoyl-diphenylphosphine oxide,2,3,4,6-tetramethylbenzoyl-diphenylphosphine oxide,2-phenyl-6-methylbenzoyl-diphenylphosphine oxide,2,6-dibromobenzoyl-diphenylphosphine oxide, ethyl2,4,6-trimethylbenzoyl-naphthylphosphinate, ethyl2,6-dichlorobenzoyl-naphthylphosphinate,1,3-dimethylnaphthalene-2-carbonyl-diphenylphosphine oxide,2,8-dimethylnaphthalene-1-carbonyl-diphenylphosphine oxide,1,3-dimethoxynaphthalene-2-carbonyl-diphenylphosphine oxide,1,3-dichloronaphthalene-2-carbonyl-diphenylphosphine oxide,2,4,6-trimethylpyridine-3-carbonyl-diphenylphosphine oxide,2,4-dimethylquinoline-3-carbonyldiphenylphosphine oxide,2,4-dimethylfuran-3-carbonyl-diphenylphosphine oxide,2,4-dimethoxyfuran-3-carbonyl-diphenylphosphine oxide, methyl2,4,5-trimethyl-thiophene-3-carbonyl-phenylphosphinate and2,4,5-trimethyl-thiophene-3-carbonyl-diphenylphosphine oxide. Preferredsensitizers included 2,4,6-trimethylbenzoyl-diphenylphosphine oxide,2,6-dimethoxybenzoyl-diphenylphosphine oxide,2,6-dichlorobenzoyl-diphenylphosphine oxide,2,3,5,6-tetramethyl-benzoyl-diphenylphosphine oxide and methyl2,4,6-trimethylbenzoylphenyl-phosphinate. Particularly preferred ashighly reactive UV sensitizers were acylphenylphosphinic acid esters andacyldiphenylphosphine oxides, where acyl is derived from adi-ortho-substituted aromatic carboxylic acid, e.g.2,4,6-trimethylbenzoic acid, 2,6-dimethoxybenzoic acid,2,6-dichlorobenzoic acid or 2,3,5,6-tetramethylbenzoic acid.Particularly advantageous was the use of photoinitiator combinations ofthe acylphosphine oxide compounds with conventional photoinitiators, forexample aromatic ketones, e.g. benzil ketals, such as benzildimethylketal, benzoin ethers and esters, e.g. benzoin isopropyl ether,α-hydroxyisobutyrophenone, diethoxyacetophenone orp-tert.-butyltrichloroacetophenone, aromatic disulfides andnaphthalenesulfonyl chlorides. Through use of the photoinitiatorcombinations it was possible, in many cases, to achieve, for comparableexposure times, lower residual styrene contents of UP resin moldingmaterials than were achieved with the acylphosphine oxide compoundsalone, though the curing activity (as measured by the temperature riseof the resin sample during exposure) was diminished.

[0104] U.S. Pat. No. 5,166,007 (1992) to Smith et al. discloses vehiclerepair products and methods using photocurable prepreg fabrics. Prepregfabrics can be formed by impregnating the fabric with a compositioncomprising a mixture of one or more ethylenically unsaturatedcopolymerizable polyesters, vinyl or acrylic ester, one or moreethylenically unsaturated copolymerizable monomeric compounds, aninhibitor and a UV sensitizer, with or without paraffins, thermallydecomposable initiators, fillers, reinforcing agents, lubricants, inertsolvents, shrinkage-reducing additives and/or other assistants usable inunsaturated polyesters. The UV sensitizer consists of one or moreacylphosphine oxide compounds as disclosed in U.S. Pat. No. 4,265,723.Particularly preferred was 2,4,6-trimethylbenzoyldiphenylphosphineoxide. Acrylic and methacrylic monomers when added to commercial resinsincreased the cure rate significantly. Preferred fabrics were comprisedof fibers which can at least partially transmit UV light so as toinitiate curing of the resin. S or E glass fabrics were found to beparticularly advantageous because of their transparency to UV light andtheir strength.

[0105] U.S. Pat. No. 5,554,666 (1996) to Livesay discloses photocurableputty and molding compositions including also aluminum trihydrate. Theresin and catalyst may be mixed just prior to use or they may beintroduced separately relying on the dynamics of the system to mix thesecomponents sufficiently. The catalyst can comprise any conventionalphotoinitiators and/or photosensitizers, with preferred photoinitiatorsbeing isobutyl benzoin ether and α,α-diethoxyacetophenone and preferredphotosensitizers being the acylphosphine oxides as disclosed in U.S.Pat. No. 4,265,723 and the photosensitizers which have a triplet energyin the range of about 54 to 72 kilocalories per mole as disclosed inU.S. Pat. No. 4,017,652. Ultraviolet radiation may be used mostefficiently if the photocurable composition contains a suitablephotoinitiator, e.g. bisphenyl (2,5-dimethybenzoyl) phosphine oxide(Palatal). The aliphatic and aromatic phosphites disclosed in the U.S.Pat. No. 4,116,788 may be utilized. Examples for the phosphites to beused as activators according to the invention includeddimethylphosphite, dioctyl-phosphite, diphenylphosphite, tri(i-octyl)phosphite, tristearyl phosphite, trimethylphosphite, triethyl-phosphite,tri(i-propyl)phosphate, tris(allyl)phosphite, didecyl-phenyl-phosphite,tris(4-nonphenyl)phosphite, and tris-4 chlorophenyl-phosphite. Thepreferred photosensitizers having a triplet energy in the range fromabout 54 to 72 kilocalories per mole which may be utilized are disclosedin U.S. Pat. No. 4,017,652 and include benzil, 3,4-benzofluorene,4-naphthaldehyde, 1-acetylnaphthalene, 2,3-butanedione,1-benzoylnaphthalene, 9-acetylphenanthrene, 3-acetylphenanthrene,2-napthaldehyde, 2-benzoylnaphthalene, 4-phenylacetophenone,anthraquinone, thioxanthone, 3,4-methylenedioxyacetophenone,4-cyanobenzophenone, 4-benzoylpyridine, 2-benzoylpridine,4,4-dichlorobenzophenone, 4-trifluoromethylbenzophenone,3-chlorobenzophenone, 4-methoxybenzophenone, 3,4-dimethylbenzophenone,4-methylbenzophenone, benzophenone, 2-methylbenzophenone,4-4′-dimethylphenone, 2,5-dimethylbenzophenone, and2,4-dimethylbenzophenone.

[0106] U.S. Pat. No. 5,554,667 (1996) to Smith et. al. discloses methodsof forming resin bonds between two or more laminates utilizingphoto-cured resins. In the preferred photocuring process the catalystcan comprise any conventional photoinitiators and/or photosensitizers.Mixtures of photoinitiators may be used. The preferred photoinitiatorsare the acylphosphine oxides as disclosed in U.S. Pat. No. 4,265,723 andthe photosensitizers which have a triplet energy in the range of about54 to 72 kilocalories per mole as disclosed U.S. Pat. No. 4,017,652. Thepreferred photosensitizers are isobutyl benzoin ether andα,α-diethoxyacetophenone.

[0107] Fillers, including reinforcing fillers and suspending fillersuseful in the present invention (in addition to short and long-fiberreinforcements) include silicon dioxide, glass (including bariumsilicate glass) flakes, glass spheres and microspheres, nephelinesyenite, feldspar, mica, pumice, calcium carbonate, alumina trihydrate,platy talc, bentonite, magnesium sulfate and other sulfates, titaniumoxide, synthetic sodium aluminum silicate (SSAS), calcium silicate,quartz, silicon carbide, alumina, tungsten carbide and pulverizedpolyacrylate. Fillers can offer a variety of benefits: increasedstrength and stiffness, reduction or prevention of fiber bloom (fiberprominence at the surface), reduced cost, reduced shrinkage, reducedexothermic heat, reduced thermal expansion coefficient, improved heatresistance, slightly improved heat conductivity, improved surfaceappearance, reduced porosity, improved wet strength, reduced crazing,improved fabrication mobility, increased viscosity, improved abrasionresistance and improved impact strength. Fillers can also havedisadvantages including limiting method of fabrication and adverselyaffecting cure and pot life of certain resins. Surface treatment ofminerals has advanced to where uniformity and type of silane, stearate,or other wetting/coupling additive can be tailored for optimumperformance.

[0108] Suspending fillers with appropriate optical properties are anecessary component of the present invention. The fillers utilized inthe present invention should, if possible, be those fillers whichpractically do not adsorb or adsorb comparatively little ultravioletlight. It is necessary that the any chosen fillers be balanced in such away that they aid in keeping the phosphor particles in suspension. Theheavy phosphorescent particles utilized in the present invention willnot stay in suspension in a typical gel coat resin or moldable resin.Sufficient suspending filler to keep the phosphorescent pigment insuspension must be added while taking care that the viscositycharacteristics of the luminescent polymer characteristics are thoseneeded for the particular application.

[0109] In general, the most useful suspending filler is silica (silicondioxide) in various forms. A flake or amorphous form of silicasuspending filler is preferred in the present invention over a flour ormicrocrystalline form. Grades from coarse to fine may be utilized, withattention being paid to rheological and thixotropic effects. In finerforms, the sand acts like a sponge and absorbs the resin. The result isa very strong and hard resin which is not brittle and is able to absorbshock, resulting in lower chip levels upon impact. Coarse grains allowheavy loading, excellent dimensional stability and predictable packing.Coarse materials can help control flashing in molding compounds and canbe used when a coarse, high-wear finish is desirable. Silica will addweight as well as strength, and thus is useful in items such as fishinglures. Colored sand or larger pebbles may be added to the luminescentthermosetting polyester for uses such as fish ponds or aquariums.

[0110] Flakes, including silica, glass, quartz and mica, represent aspecial class of discontinuous reinforcing fillers. Flake reinforcementshave an advantage over fibers in that they provide reinforcement in aplane instead of along a single axis. In flake-reinforced composites,properties such as modulus, strength, thermal expansion, and shrinkageare considered planar isotopic.

[0111] Crystalline silicas are low oil-absorption products of high Mohs'hardness occurring naturally as sand, quartz, tripoli and novaculite.The low oil absorption results in easy dispersion of the filler and lowviscosity of the resin-filler mix. Precipitated and fumed silicas aresynthetic premium products, very useful for improvement of suspensioncharacteristics, modification of thixotropic characteristics andreinforcement. Silica has additional benefits as a flow agent and inhelping to prevent concussion to the phosphorescent particles.

[0112] Other preferred suspending fillers include microspheres, milledfiberglass (typically milled with a 1:1 to 20:1 or more aspect orlength-to-diameter ratio) and other milled fibers and short fibers,nepheline syenite, feldspar, glass flakes, pumice and mica. Calciumcarbonate finds some use as a suspending filler, particularly incrystalline forms such as calcite. Magnesium sulfate, calcium sulfate,barium sulfate and other sulfates in crystalline form also find use. ATH(alumina trihydrate, actually a crystalline aluminum hydroxide) alsofind some use as a suspending filler in addition to use as a flame andsmoke retardant. As talc, carbon blacks and other powdery fillerstypically are not suspending fillers, great care must be taken inutilizing them in conjunction with the present invention (talc also hasa tendency to congeal if overemployed and carbon blacks may interferewith luminescence). Guiding principles and specific applications arediscussed further below.

[0113] Nepheline syenite and feldspar may lend particular benefits togel coats and the present invention by helping to provide weatherable,glossy surfaces and improved stress-cracking resistance. They are hard,easily wet and dispersed, enable transparency and translucency inpolymers with good clarity, exhibit chemical, weather and abrasionresistance, and are suitable for food-grade contact applications. Theparticle surfaces are smooth and grasslike and impart almost no color,and therefore the full masstone effects of color and luminescentpigments are realized. As with all fillers in gel coats, they reduceshrinkage on curing and thus prevent warping or stressing of thelaminate and peeling of the gel coat. Because fillers also reduceelongation and impact resistance in rigid thermosets, it is essentialthat a resilient polyester or more flexible type be used in formulationswhere feldspar or nepheline syenite are used.

[0114] Hollow and solid glass microspheres are widely used in resinsystems as their sphericity, controlled particle size and density andother unique properties can improve performance and/or decrease costs.Solid glass spheres range in size from 5 to 5000 μm. Microspheres, bothsolid and hollow, have been arbitrarily defined as products with themajority of particles less than 200 μm in diameter. The size most oftenused in plastics is less than 44 μm. They can be glass, ceramic, carbon,organic or polymeric; glass microspheres are generally preferred in thepresent invention. Both solid and hollow spheres act as tiny bearings,with a minimum ratio of surface are to volume, which reduces viscousdrag and provides better flow properties. As microspheres are free oforientation and have no sharp edges, they produce a smoother surfacewith more uniform shrinkage in the plastic than can be obtained withfibers or many randomly shaped fillers. Solid spheres are typically usedwhere strength is a concern. They modify properties of the resin,especially flexural modulus and compressive strength, improve abrasionand corrosion resistance and reduce mold shrinkage and cycle time. Theprimary functions of hollow spheres are density reduction, themodification of physical properties including improved stiffness andimpact resistance, reduced crazing compared to non-spherical fillers(particularly in flexible applications) and the ability to displacelarge volumes of higher priced polymer. The surface of both hollow andsolid microspheres are available with special coatings to enhancesphere-resin bonding. Solid glass spheres or beads find particular usein applications such as crosswalks, curb markers and numbers, stairtreads and other similar applications in amounts up to 30%.

[0115] Magnesium sulfate is useful for enhancing the brightness of theluminescent polymers. As with other fillers, a crystalline or flake formis preferred to a powdery form. Calcium sulfate and barium sulfate aresimilarly useful.

[0116] To improve weatherability of the polymer composition, to preventpremature, unwanted polymerization of the polymerizable substances, andto provide zinc sulfide phosphors with protection from “overloading” or“burning out,” a mixture of ultraviolet stabilizers is preferably added.With polymers, UV energy is absorbed by chemical groups known aschromophores, such as a double bond in the polymer structure, residualmonomer or catalyst, aromatic or other double-bonded contaminants in anyof the ingredients or hydroperoxide or carbonyl groups resulting fromthermal oxidation during processing. When acted upon by ionizing energy,many phosphorescent compounds gradually decompose with a resultant lossof luminescence. The photochemical “greying” of zinc sulfide compoundsoccurs when exposed to UV light in the presence of humidity. This isthought to be due to the deposition of zinc on the crystal surfaces,which eventually results in a decrease in the light output.

[0117] “Greying” can be prevented by eliminating one of its causes, viz.atmospheric humidity or UV radiation. Atmospheric humidity and UVradiation may also promote a time-dependent decrease in brightnessduring the operation of electroluminescent polymers described herein. Itis therefore important that sufficient UV stabilizer or stabilizers arepresent in the photoluminescent and electroluminescent polymers whenphosphors containing zinc sulfide are utilized. With phosphors which arenot sensitive to UV light, such as alkaline earth metal aluminateoxides, the UV stabilizers need be present only in sufficient quantityto protect the polymer.

[0118] With regard to the post-cure polyester thermoset polymers usefulin this invention, if UV energy absorbed during usage is not rapidlydissipated, it will slowly begin to break the chemical bonds in thepolymer's molecular chain; the lower-molecular-weight chain fragmentswill no longer exhibit the properties of the original polymer. It alsogenerates free radicals, initiating and propagating a chain-degradationreaction. The end results can be embrittlement, discoloration, chalkingand loss of physical properties. UV stabilizers interrupt this sequenceof events by mechanisms including inhibition of sequence initiation viaincorporating additives to screen UV energy (screeners), topreferentially absorb it (absorbers) or to quench the excited state(quenchers) and via incorporating additives that will react chemicallywith the free radicals and hydroperoxides as soon as they are formed torender them harmless by interrupting the degradation sequence (includingfree-radical scavengers, antioxidants and peroxide decomposers).

[0119] Typical ultraviolet light screeners are pigments which render thepolymer translucent or opaque and absorb or reflect UV light. Usefuloptional screeners include titanium dioxide and zinc oxide, with organicsynergists such as zinc dialkyl dithiocarbamates (methyl and ethylzimate), nickel-organic salts and phosphites. Care must be taken inusing ultraviolet light screening and absorbing pigments in the presentinvention in order to prevent excessive screening of the phosphorescentpigments. Care must also be taken that the amounts of such pigments donot preclude curing of the interior of the coating. The maximum amountis therefore related to the thickness of the coating to be cure—thincoatings may tolerate more ultraviolet light absorbing pigment thanthick coatings.

[0120] UV absorbers inhibit initiation of the degradation process.Materials in this class compete with the polymer chromophores for UWenergy and win because their absorptivity is orders of magnitude greaterthan that of the chromophores. Once they absorb the UV energy, theyconvert it into a nondestructive form, infrared energy, which isdissipated harmlessly as heat. UV absorbers include benzophenones suchas 2,4-dihydroxy benzophenone, substituted 2-hydroxy-4-alkoxybenzophenones (such as 2-hydroxy-4-methoxy benzophenone) and hydroxybenzophenones containing sulfonic acid groups and the like (high-alkylsubstituents such as ocytl, decyl and dodecyl groups offer reducedvolatility and increased compatibility); benzoates such as dibenzoate ofdiphenylol propane, tertiary butyl benzoate of diphenylol propane,salicylates, resorcinol monobenzoates and aryl or alkyl hydroxybenzoates and the like; triazines such as 3,5-dialkyl-4-hydroxyphenylderivatives of triazine, sulfur containing derivatives ofdialkyl-4-hydroxy phenyl triazine, hydroxy phenyl-1,3,5-triazine and thelike; triazoles such as 2-phenyl-4-(2,2′-dihydroxy benzoyl)-triazole,substituted benzotriazoles such as hydroxy-phenyltriazole andsubstituted hydroxy-benzotriazoles and derivatives of 2(2′-hydroxyphenyl) benzotriazole and the like; oxanilides and substitutedoxanilides; acrylic esters; formamidines and any mixtures of the above.Absorbers are more effective in thicker cross sections than in thinones, and they may not provide the surface with sufficient protection.The addition of selected UV absorbers for the purpose of the lightstabilization of the cured products in some cases slightly reduces therate of UV curing, but this reduction is within acceptable limits.Suitable absorbers for the photocurable luminescent resins of thepresent invention include those from the hydroxybenzophenone, salicyclicacid ester and hydroxyphenylbenztriazole series.

[0121] UV quenchers (excited-state quenchers) also inhibit initiation,although they function a bit later in the sequence than absorbers. Theyaccept excess energy from polymer chromophores that have absorbed UVenergy and are in an excited state, returning the chromophore to theground state and leaving the quencher in the excited state. The quencherthen dissipates its acquired energy harmlessly as heat. Quenchersinclude organic nickel compounds such as[2,2′thiobis(4-octylphenolato)]-n-butylamine nickel II, nickel salts ofthiocarbamate, and complexes of alkylated phenol phosphonate withnickel.

[0122] UV scavengers and decomposers operate later in the sequence,inhibiting propagation rather than initiation, through a combination ofscavenging and terminating free radicals and decomposing hydroperoxidesto harmless nonradical species. This is similar to the function ofantioxidants. In fact, secondary antioxidants, organic nickel quenchersand carbon blacks have been cited as decomposers, but, to the extentthat they are consumed in a peroxide reaction, primary function suffers.Even with absorbers and quenchers, free radicals are almost alwaysgenerated; thus the importance of the mechanism of free-radicalscavenging and termination, where the stabilizer reacts with radicalsformed in initial steps of the degradation sequence. UV scavengers anddecomposers include hindered amines (which may function as excited-statequenchers or peroxide decomposers in addition to their main function,free-radical scavenging and termination) such as bis(1,2,2,6,6pentamethyl-4-piperidinyl sebacate), di[4(2,2,6,6 tetramethylpiperidinyl)] sebacate and other tetramethyl piperidine compounds andthe like. Characteristic of the hindered-amine type is the tetramethylpiperidine structure; a nitroxy radical acts as scavenger for R. andROO. radicals and is regenerated in the process (the cyclic regenerationbeing exceedingly useful for UV stabilization). Unlike the absorbers,the hindered amines provide surface protection and are effective in thinsections. Unlike the quenchers, they do not impart color. The hinderedamines may be used in combination with absorbers and/or quenchers tomaximize UV protection.

[0123] To get flame retardance, polyesters are typically halogenated(chlorinated and/or brominated) and/or use high levels of aluminatrihydrate (ATH) or other flame retardants. Both of these approaches areuseful with the present invention. The flame retardant resins describedherein also are particularly useful in that they tend to protect theother polymer resins and the phosphor from UV light.

[0124] Flame-retardant polyester resins are obtained by using thereactive intermediates chlorendic anhydride, tetrabromophthalicanhydride, dibromoneopentyl glycol, tetrachlorophthalic anhydride and/orother halogenated acids and glycols. Decabromodiphenyl oxide (DBDPO)(ether), bromobisphenol-A and pentabromodiphenyl oxide blends also findsome use. Ionic bromines including phosphonium bromide are utilized forsynergistic combinations. The dispersability and compatibility ofbromine-containing additives with the polymer matrix are extremelyimportant for achieving a good balance between flame protection andprocessability. Many halogen-containing flame retardants also includestabilizers to increase shelf life, improve thermal stability andprotect processing equipment from corrosion.

[0125] ATH is a dry, light powder that functions by absorbing heat, byevolving steam to dilute the combustible gases being generated, and byproducing a non-flammable char barrier between the heat and thematerial. ATH also functions as an extender and as a smoke suppressant.Loading levels are typically relatively high. Various surface treatmentscan be used to enhance the various properties of ATH-filled polymers,including stearate coating and treatment with silanes, titanates andphosphates to improve properties such as flex strength, flex-whitening,filler handling, wetout, viscosity and mold flow.

[0126] Typically ATH materials for sprayup are designed to yield low mixviscosities at high filler loadings as well as good glass wetting androllout with minimal air entrapment and good suspension characteristics.In a wet-layup system in which the glass is placed in the mold and thefilled resin system distributed on it, ATH particle size distributionshould be optimized to prevent filtration of the filler and to providegood pigmentation. Pure-white ATH is generally preferable to calciumcarbonate as a filler as it imparts a degree of translucency notpossible with calcium carbonate due to the different indices ofrefraction.

[0127] Other retardants which may find use include magnesium hydroxide,those based on phosphorus such as phosphate esters, vinylphosphonatessuch as the bis(hydrocarbyl)vinylphosphonates and their condensationproducts, antimony oxide, zinc borates, barium metaborates andmolybdenum compounds. Magnesium carbonate is an excellent smokesuppressant. Mixtures of compounds are often employed and are oftenpreferred for synergistic flame retardance.

[0128] Foaming agents, or blowing agents, and initiators may be usefulin molding processes and may be utilized if desired with the presentinvention. Suitable physical foaming agents include compressed gases andthe lower boiling hydrocarbons and halogenated derivatives. Chemicalfoaming agents useful with the present invention include sulfonehydrazide blowing agents, isocyanate-based agents, nitrogen-based agentsand other such agents known to the art. Foaming agents have theadditional benefits of helping to keep the phosphorescent particles insuspension and tending to force phosphorescent particles to the surfaceof the molded article. Since some foaming agents are substantiallysoluble in the resins utilized in the present invention, the luminescentpolymers will contain identifiable proportions of foaming agent if suchagents are utilized.

[0129] Another useful component of unsaturated polyester resins are flowcontrol agents such as polyacrylic acid, polyalkylacrylates, polyethermodified dimethyl polysiloxane copolymer and polyester modifiedpolydimethyl siloxane. Flow control agents are typically used in amountsof about 0.1-5% by weight. Other useful additives may includelubricants, processing aids and primary antioxidants.

[0130] Reinforced plastics are composites in which a resin is combinedwith a reinforcing agent to improve one or more properties of theplastic matrix. The reinforcement is a strong inert material bound intothe plastic to improve its physical properties (such as strength,stiffness or impact resistance) or to impart specific chemical orthermal properties. The reinforcing agent can be fibrous, powderedspherical, crystalline, or whisker and can be made of organic,inorganic, metallic or ceramic material. The strength-to-weight ratio ofreinforced plastics is attributed largely to the nature of thereinforcements, with the matrix material or resin serving to bond thereinforcements together and to transmit the load to the reinforcingfibers or other material.

[0131] Micro and short fibers will do a reinforcing job that is notpossible with either continuous fibers or fillers for injection molding,extrusion and transfer molding. This class includes whiskers,microfibers, mineral fibers, chopped and milled fibers, short metalfibers and chopped metal-coated fibers. Whiskers are theultimate-strength short-fiber reinforcement because they are small witha high degree of crystalline perfection. Microfibers are generallypolycrystalline fiber bundles and do not possess the purity andcrystalline perfection of a true whisker, with a consequent effect onthe mechanical properties. Mineral fibers are short fibers found innature that are processed for use. With the phasing out of asbestos,wollastonite (calcium metasilicate, CaSiO₃) is the mineral fiber ofprimary importance. It has the advantage of a pure-white, whollyacicular (needlelike) form. Chopped and milled fibers are made fromcontinuous fibers such as glass fibers, carbon, boron and aramid fibers,as well as metal fibers. The properties of the chopped and milled fibersare related to structure, size, and manufacturing method. Resilientthermoplastic fibers (ad fabrics) may be specifically engineered toimpart needed durability to brittle thermosets and for properties suchas non-abrasiveness and shatter-resistance. Metallic fibers,particularly stainless steel fibers, make an excellent conductivereinforcement, but their high price excludes them from most applicationswith the introduction of much less expensive conductive fibers andfillers, including aluminum coated glass fiber, sliced-aluminum-foilribbons and melt-spun aluminum fibers. Ceramic fibers offer hightemperature resistance, high modulus and compressive strength andoutstanding chemical resistance. Suitable synthetic organic highmolecular weight polymers may be utilized, e.g. nylon, polyacrylonitrileand polyesters, for example terephthalates. Resilient thermoplasticfibers have been specifically engineered to impart needed durability tobrittle thermosets.

[0132] Any fibrous reinforcement must meet specific end-use requirementsof strength and cost. For many laminates of low strength requirements,paper is an excellent reinforcement. The preferred fibrous reinforcementin the present invention is usually fiberglass. Several forms of glassfiber products can be used for reinforcing thermosetting plastics. Theseinclude woven fabrics, continuous strand roving, chopped strand, wovenroving, nonwowen, mats (both continuous strand and chopped strand),yarn, milled fiber, etc. Surfacing mats or veils (open-weave, soft-typecloth glass fiber and synthetic nonwoven fabrics or mats with athickness of ˜0.25 mm.) may be used to support resin-rich surfaces inmatched die molding and other processes. In general, for open moldingand press molded laminates, woven fabrics are more useful and morecommon. For molded products, nonwoven mats are more versatile and lessexpensive. A nonwoven form may be preferred for cost considerations. Ifunusually high strength at high temperatures is essential regardless ofcost, more exotic reinforcements of graphite, carbon fiber, metallicoxide fibers, ceramic, aramid (aromatic polyamides), hybridaramid/carbon, carbon/glass hybrids, ceramic fibers (defined asnonmetallic inorganic fibrous materials such as refractory ceramicfiber, alumina fibers, boron fibers and silicon carbide monofilament,whisker and fiber forms), alumina boria-silica or alumina chromia-silica(such as Nextel®) or other materials may be required.

[0133] Glass fiber reinforcement typically improves the properties ofthe polymer composite, resulting, for example, in high strength,dimensional stability, resistance to temperature extremes, corrosionresistance, desirable electrical properties and ease of fabrication.Several factors determine the physical properties of reinforced moldedparts. Most important is the amount of fiber used—the ratio of glass toresin. Strength increases in direct proportion to the glass content.Fiber length and orientation affect load-bearing capability andcontinuity of stress transfer. Unidirectional orientation providesoptimal strength in one direction and makes it possible to achieve up to80% glass content. Bi-directional orientation, with a glass content upto 75%, usually places fibers at right angles to each other to providestrength in both directions. Multi-directional or random orientationprovides equal but lower strength in all directions, with a glasscontent up to 65%.

[0134] Silicate base fiber glass is manufactured from a melt of SiO₂ andother oxides that are allowed to cool in fiber form withoutcrystallization (amorphous form). Glass reinforcements having a varietyof compositions, filament diameters and forms are useful in thisinvention.

[0135] Various fibrous silicon oxide materials can be used. Examples oftypes of glass include, but are not limited to, type A glass (an alkaliglass which is close to the standard soda lime silica window or bottleglass composition); type E (electrical) glass, probably the type mostwidely used for reinforced plastics (a boroaluminosilicate glass withgood resistance to water, fair resistance to alkali and poor resistanceto acid); type C glass (a calcium aluminosilicate); type S and type Rglass (high-strength, high-modulus type glass for advanced composites);and type D glass (improved electrical performance and lower density).

[0136] The diameter of the glass fiber is preferably less than 20micrometers (mu m), but may vary from about 3 to about 30 mu m. Glassfiber diameters are usually given a letter designation between A and Z.The most common diameters used in glass reinforced thermoplastics areG-filament (about 9 mu m) and K-filament (about 13 mu m), althoughfibers up to P-filament (about 18 mu m) may occasionally be utilized.Continuous filament strands are generally cut into lengths of ⅛,{fraction (3/16)}, ¼, ½, ¾, and 1 inch or longer for compoundingefficacy in various processes and products.

[0137] Commercial glass fiber reinforcement products are usually sizedeither during the fiber formation process or in a posttreatment, andthus are sold with sizing (organic carrying medium) materials alreadyincorporated. The amount of sizing on the glass fiber product typicallyranges from about 0.2 to about 1.5 weight percent based on total weightof the glass and the sizing, although loadings up to 10 percent may beadded to mat products. Sizing compositions for use in treating glassfibers usually contain a lubricant (generally amine-type lubricants),which provides the protection for the glass fiber strand; a film-formeror binder that gives the glass fiber strand integrity and workability; acoupling agent that provides better adhesion between the glass fiberstrand and the polymeric materials that are reinforced with the glassfiber strand; and other additives such as emulsifiers, wetting agents,nucleating agents and the like. Various sizing compositions have beendeveloped for glass fiber reinforcements to provide improved adhesionbetween various polymeric materials and the glass fiber. The lubricant,film-former, and coupling agent can be a single compound or a mixture oftwo or more compounds.

[0138] The film former is usually water soluble or water emulsifiableduring processing and must be non-sensitive to water after curing.Examples of film-formers include, but are not limited to, polyesters,epoxy resins, polyurethanes, polyacrylates, polyvinyl acetates,polyvinyl alcohols, styrene-butadiene latexes, starches and the like.

[0139] The coupling agent is usually a silane coupling agent that has ahydrolyzable moiety for bonding to the glass and a reactive organicmoiety that is compatible with the polymeric material which is to bereinforced with the glass fibers. Complex chrome and titanatecrosslinking or coupling agents also may be utilized.

[0140] Carbon fibers are used in such areas as automotive, aerospace andsporting-goods applications. They offer high modulus and strength, lowdensity, low thermal coefficient of expansion, low coefficient offriction and excellent resistance to most environmental-exposureconditions and chemicals.

[0141] Ceramic fibers are continuous fibers of metal oxides. The majoradvantages of these fibers are very high temperature resistance plushigh modulus and compressive strength. They also have outstandingchemical resistance and can be woven into fabrics.

[0142] Several types of conductive fillers and fibers are known to beuseful for lowering the innate electrical resistivity of plastics—thatis, to impart partial conductivity. This is done at three levels ofconductivity—1) antistatic or electrostatic dissipation (ESD); 2)semiconductive, mostly for power-cable shielding; and 3) conductive, toprovide shielding against electromagnetic interference (EMI) inelectronic packages and cabinetry. Addition of conductive fillers andfibers (such as stainless steel fibers) may prove particularly usefulwith the present invention via increased electrical conductivityproviding electrically conductive luminescent polymers and via increasedthermal conductivity for thermoluminescent applications.

[0143] Another group of materials that has been found to be useful inconjunction to brighten and improve reflective qualities with thepresent invention are luminescence enhancers such as opticalbrighteners, fluorescent whiteners, color brighteners and spectrumenhancers. Fluorescent daylight pigments are particularly effective inconjunction with UV stabilizers and benefit from UV protection.

[0144] Other materials that may prove useful with the present inventioninclude coral extracts, isolates and derivatives for UV protection,daylight fluorescent pigments, pearlescent pigments, metallic flakepigments, thermochromics (producing heat-activated color changes),photochromics (producing light-activated color changes), diamond-likematerials from solutions of polyphenylcarbyne, color concentrates,adhesives etc.

[0145] The following descriptions are examples of materials that may beutilized to practice the present invention. They should be considered asexamples and not as unduly limiting.

[0146] AQUAGUARD 83279 clear gelcoat (FGI product code no. 12217),obtained from fiber glass international (FGI, a division of A. C.Hatrick Chemicals Pty. Ltd.) of Southport, Queensland, Australia, is anorthophthalate, neopentyl glycol and propylene glycol based polyestergelcoat containing alumina trihydrate as a flame retardant. AQUAGUARDgelcoat is a prepromoted thixotropic spray grade developed primarily foruse in sanitaryware applications which also finds use in applicationssuch as swimming pools. AQUAGUARD gelcoat is highly durable withexcellent flow/leveling properties, rapid air release, good sag andtriping/wrinkling resistance with excellent weathering resistance and ahigh degree of flexibility. AQUAGUARD has a gel time (2% v/w NR2O MEKP)of 10-15 minutes.

[0147] JS AQUAGUARD Culture Finish/Clear Gelcoat is a clearpolyester/styrene gel coat used as a topcoat for swimming poolscontaining fumed silica, benzophenone and/or phenolic UV inhibitors andmetal naphthenates and octoates as activators.

[0148] ESCON EX80 (61-286), obtained from FGI of Australia, is a lowviscosity, low reactivity, high clarity, acrylic modified polyesterresin designed for decorative castings and embedding where excellentcolor and clarity are desired. ESCON EX80 is supplied pre-acceleratedand stabilized to minimize discoloration and deterioration by UV light.On the addition of 1% MEKP at 25° C. a gel time of from 45-60 minutescan be expected. Curing proceeds relatively slowly once the resin hasgelled; very low exotherm (approximately 40-50° C.) characteristics givea slow even cure over a period of several hours, ensuring that crackingand discoloration due to overheating is avoided in larger casting. Thelow viscosity of ESCON EX80 is advantageous in allowing fast release ofair bubbles before gelation occurs. Post curing of the finished articleis essential.

[0149] ESCON CR64 (61-283), obtained from FGI of Australia, is a mediumviscosity, low reactivity, unsaturated fumaric acid and phthalic(orthophthalate) based resin. ESCON CR64 (61-283) may be substitutedinterchangeably in the examples herein for the ESCON EX80 (61-286) resindescribed above. ESCON CR64 is a high clarity polyester designed for theproduction of decorative castings where excellent color and clarity areessential. It is supplied pre-accelerated for room temperature curingwith a gel time of 20-30 minutes at 25° C. with 1% MEKP and containsstabilizers to minimize discoloration by UV light. For very largecastings and laminates it may be preferable to use the slower curingcasting resin ESCON EX80.

[0150] POLYLITE® 33-100-01 (Formerly Koppers 1061-5 West Coast), aReichhold Chemicals, Inc. unsaturated polyester resin obtained from FGIof Australia, is an orthophthalic, wax-containing laminating resin with40-50% styrene monomer.

[0151] NORPOL 62-303 is a Jotun Polymer AS, Norway (now Reichhold ASNorway) product obtained from FGI of Australia. NORPOL 62-303orthophthalic polyester resin is a medium reactive general purpose lowstyrene emission (L.S.E.) resin designed for hand or spray lay-upapplication, suitable for laminate thickness from 3-7 mm appliedwet-on-wet. It is thixotropic and has a built-in accelerator systemgiving low exothermic temperature combined with relatively long geltimeand rapid curing. It has a geltime (2% MEKP) of 30-45 minutes in summerand 20-30 minutes in winter.

[0152] DION® ISO 33-434-00 (formerly DION® Iso 6631T), a ReicholdChemicals, Inc. unsaturated polyester resin, is a wax free, highmolecular-weight, rigid isophthalic laminating resin with excellentmechanical properties and heat resistance containing a maximum of 55%styrene monomer.

[0153] POLYLITE® 61-358 and POLYLITE® 61-359, Reichold Chemicals, Inc.products obtained from FGI of Australia, are high performanceisophthalic wax-free polyester resin which are thixotropic, prepromoted,easy to roll out with viscosity suitable for spray-up, low exotherm inthick sections and have a high degree of chemical resistance. POLYLITE®61-358 is wax free. POLYLITE® 61-359 is a wax containing low styreneemission (L.S.E.) grade. The gel time at 25° C. is approximately 15minutes with 1% MEKP.

[0154] POLYLITE® 61-340 and POLYLITE® 61-341, Reichold Chemicals, Inc.products obtained from FGI of Australia, are rigid, thixotropicprepromoted orthophthalic laminating resins formulated for production ofreinforced plastic parts by spray-up or hand lay up techniques.POLYLITE® 61-340 is wax free and POLYLITE® 61-341 contains wax. The geltime is approximately 25 minutes at 25° C. with 1% MEKP. Color changegives visual indication of catalysation, gel and cure, with low colorwhen cured.

[0155] ESCON EX663P 61-627, obtained from FGI of Australia, is a generalpurpose, self-extinguishing orthophthalate (phthalic) based laminatingresin containing halogenated compounds, particularly useful when clearlaminates are required. The resin contains 30-40% styrene monomer and isthixotropic, prepromoted and formulated for spray and hand applicationswith a gel time at 25° C. (1% MEKP) of 20-30 minutes. The resin whenfully cured will conform to the following standards: Rated Class 2-BS476-Part 7, rated self-extinguishing to ASTMD 635, and having a ratingto AS1530-Part 3 1982 of Ignitability Index 16, Spread of Flame Index 9,Heat Evolved Index 10 and Smoke Developed Index 9. Improved fireretardancy can be obtained by the addition of additives such as antimonytrioxide or alumina hydrate.

[0156] POLYLITE® 61-428, a Reichold Chemicals, Inc. product obtainedfrom FGI of Australia, is an isophthalic flexible casting resincontaining 35-37% monomer which gives low color and highly flexiblecastings. It is used with fillers in reproduction castings and as ablend with other resins where it adds flexibility and reduces the amountof heat generated during the cure.

[0157] ESCON 400 (61-440), obtained from A. C. Hatrick Chemicals Pty.Ltd. of Botany, New South Wales, Australia, is a low reactivity, mediumviscosity, fully flexible isophthalic resin with a monomer content of30% and a room temperature gel time of approximately 20-30 minutes.ESCON 400 is used to modify rigid resins to improve impact resistanceand minimize stresses and shrinkage and is used in the manufacture offilled patching putties characterized by excellent adhesion and storagestability.

[0158] POLYLITE® 61-801 wax solution, a Reichold Chemicals Inc. productobtained from FGI of Australia, is a 5% solution of paraffin wax instyrene monomer. POLYLITE® 61-801 serves to reduce or eliminate surfacetack caused by air inhibition during cure and improves surface finish,while the film forming characteristics of the paraffin wax also assistin reducing styrene emission from polyester resins. It is also usefulfor improving surface smoothness and luster and reducing the need for amold release agent.

[0159] SUNREZ® 8411 is a photocurable resin of hydroxypropylmethacrylate in a polymer base.

[0160] SUNREZ® 2010C is a photocurable casting resin.

[0161] SUNREZ® 2010C is a photocurable flexible resin.

[0162] SUNREZ® Sunthix Thixotrope is a thixotropic additive.

[0163] AEROSOL R2O2 fumed silica, obtained from FGI of Australia,is >99.8% SiO₂ with a BET surface area of 100±20 m²/g, an averageprimary particle size of 14 nm and a tapped density of approximately 50g/l.

[0164] Q-CEL “5 Series” grade 570 hollow microspheres, a PQ AustraliaPty. Ltd. product obtained from FGI, Australia, are organosiliconsurface-modified sodium borosilicate high performance microspheres withvery good strength. They have a bulk density of 0.34 g/cc, an effectivedensity (liquid displacement) of 0.70 g/cc, and a particle size range of1-50 microns, with a mean particle size of 20 microns. They are easilydispersed into liquid systems and remain free flowing. The viscosity ofthe thermosetting polyester base material will increase significantlyless per volume imparted when adding Q-CEL in place of other suspendingfillers, and as such can be useful in adjusting final viscosity. Highshear, high energy mixing is not necessary and can damage or break thesphere.

[0165] CAB-O-SIL® M-5 Untreated Fumed Silica, a Cabot Corp. productobtained from FGI of Australia, is a high purity silica which providesrheology control, reinforcement and/or free flow. It has an amorphousform, a surface area of 200±25 m²/g, a bulk density of 40 g/l (2.5lb./ft.³), a refractive index of 1.46 and an average particle(aggregate) length of 0.2-0.3 microns.

[0166] HIGILITE H320 (E1000F) Alumina Trihydrate, a Showa AluminumIndustries K.K. product obtained from FGI, Australia, is a fine aluminumhydroxide with excellent whiteness and superior optical character(refractive index of 1.57). HIGILITE is 99.9% Al(OH)₃, with a meanparticle size of 10 μm, a bulk density of 0.6 g/cm³ and 1.0 g/cm³tapped, a whiteness of 98 and a BET specific surface area of 2.0 m²/g.

[0167] UCAR® Thermoset Microballoons (Phenolic microballoons), a UnionCarbide Chemicals (Australia) Pty. Ltd. product obtained from FGI ofAustralia, are phenol-formaldehyde resin hollow spheres.

[0168] Talc TM, a Commercial Minerals Limited of Australia productobtained from FGI of Australia, is a hydrous magnesium silicate mineralthat is predominantly finer than 75 microns (residue>75 microns 1.5%maximum). The talc has a refractive index is 1.59, with a reflectance(457 mu) of 84.

[0169] BEKI-SHIELD® conductive fibers, a Bekaert Fibre Technologiesproduct available from Specialised Conductives Pty. Ltd. of Australia,are 8 micron diameter draw stainless steel wires available in bothcontinuous form and chopped fiber form with various polymeric binders.

[0170] Calcium carbonate, an APS Ajax Finechem of Australia product, wasobtained from FGI of Australia.

[0171] Magnesium Sulphate dried (approximately MgSO₄.3H₂O), an APS AjaxFinechem of Australia product, was obtained from FGI of Australia.

[0172] LUMILUX® Green N-PM 50090 long afterglow ZnS:Cu (zincsulfide:copper) pigment is a Riedel-de Haën GmbH of AlliedSignal Inc.product obtained from Hoechst Australia Ltd. LUMILUX® Green N-PM 50090has an emission spectrum peak of approximately 530 nm. and a broadexcitation spectrum with a peak at approximately 380-400 nm. Theafterglow brightness according to DIN 67510 Part 4 (mcd/m2) is 47 after5 min., 25.4 after 10 min., 8.8 after 30 min., 4.5 after 60 min. and 2.3after 120 min. The decay to 100×threshold of perception (=0.3 mcd/m2)occurs after 960 min. LUMILUX® Green N-PM 50090 ZnS:Cu also containssome selenium and silicon is multiply activated by numerous elements inaddition to copper, including gallium, indium, magnesium, gold, silver,calcium, manganese and iron. The density is 4.1 g/ml. Frequentexcitation of the phosphorescent pigment does not impair the luminousproperties.

[0173] LUMILUX® Green SN-pigments, available from Riedel-de Haën ofGermany, are a long-lasting afterglow luminescent alkaline earthaluminate doped with rare earths. LUMILUX® Green SN-pigments have anexcitation maximum of 380 to 400 nm, an emission maximum of 520 nm and adensity of approximately 3.5 g/ml. The afterglowing effect is around tentimes brighter than that of the classical zinc sulfides such as theLUMILUX® Green N-PM 50090 described above, with a duration of afterglow(down to 0.3 mcd/m²) of up to 3600 minutes. The initial radiantintensity of the afterglow can be increased by up to 30% when excitationis carried out with illumination levels of 3000 to 5000 Lux instead ofthe usual 1000 Lux. The LUMILUX® Green SN-pigments are stable againstgreying but are sensitive to water. They are sensitive to spectralexcitation beginning in the blue part of the visible spectrum andextending up to well into the longwave UV wavelengths. If the level ofillumination available for excitation is low (<300 Lux) or if only afilament bulb is available, the afterglow effect is of a very muchreduced level even if “charging” is carried out for a very long time.The maximum afterglow effect is produced with excitation by daylight orhigh strength, cold-white fluorescent lamps. LUMILUX® Green SN-FO 50069has a density of 3.4 g/cm³, a screen discharge size of less than 80 μm(less than 1% oversized particles) and a particle size distribution d₅₀of 40 μm±4 μm. The excitation spectrum has a maximum at approximately370 nm, with a phosphorescence spectra maximum at approximately 520 nm.LUMILUX® Green SN-FOG 50089 has similar properties with a screendischarge size of less than 125 μm (less than 1% oversized particles)and a particle size distribution d₅₀ of 50 μm±5 μm.

[0174] LUMILUX® Effect N-series pigments, available from Riedel-de Haën,include green, blue, yellow, yellowgreen, orange and red afterglowpigments based on activated zinc sulfides. LUMILUX® Effect Blue N 50050has a density of approximately 3.2 g/cm³ and an average particle size of15 μm. LUMILUX® Effect Red N 100 50031 is a zinc calcium sulfide with adensity of approximately 2.5 g/cm³ and an average particle size of 17μm.

[0175] LUMINOVA® Green (G) and Blue Green (BG) strontium oxide aluminatelong afterglow phosphorescent pigments are manufactured by Nemoto & Co.Ltd. of Japan under U.S. Pat. No. 5,424,006 (discussed above) and areavailable from United Mineral & Chemical Corp., Lyndhurst, N.J., USA.The initial afterglow brightness and afterglow period is up to ten timesthat of conventional zinc sulfide based phosphors. They may be activatedby a wide wavelength band (200-450 nm) but best results are obtainedwith an activation under 365 nm, with most effective energy saturationobtained from light sources which are rich in UV light. Afterglowbrightness increases with increase in light source intensity; afterglowbrightness is also proportional to the intensity of UV contained in theexcitation light. LUMINOVA® Green (G) has an emission peak of 520 nm,while LUMINOVA® Blue Green (BG) has an emission peak of 480 nm.Afterglow extinction (time required for afterglow brightness to diminishto 0.32 mcd/m²) is >2,000 minutes. LUMINOVA® pigments are available in avariety of particle sizes with D₅₀ particle sizes varying from 1.45 μmto 42.00 μm. Coarser particles will have better brightness andafterglow. LUMINOVA® Green (G) has a density of 3.6; LUMINOVA® BlueGreen (BG) has a density of 3.9.

[0176] UMC Phosphorescent pigments, available from United Mineral &Chemical Corp., are sulfide based pigments available in a variety ofemission colors and daylight fluorescent colors. UMC 6SSU is a ZnS:Cuphosphor with an emission peak at 529±4, a specific gravity of 4.1 andan average particle size of 22. UMC GSR is a yellow emitting ZnS:Cu,Mnphosphor with emission peaks at 520 and 570, a specific gravity of 4.1and an average particle size of 22 nm. UMC BAS is a (Ca,Sr)S:Bi blueemitting phosphor with emission peaks at 450 and 580, a specific gravityof 3.2 and an average particle size of 35 nm.

[0177] TINUVIN® 292, obtained from Ciba-Geigy Australia Ltd., is a UVstabilizer and spectrum enhancer (color brightener) containing bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate andmethyl-(1,2,2,6,6,-pentamethyl-4-piperidyl) sebacate. It is recommendedfor use in concentrations of 0.5-2% based on binder solids.

[0178] TINLVIN® 171, obtained from Ciba-Geigy Australia Ltd., is a UVstabilizer of 2-(2-hydroxy-benzotriazole-2-yl)-4-methyl-6-dodecylphenol.

[0179] TINUVIN® 384-2 is a Ciba Specialty Chemicals is liquid UVabsorber of the hydroxyphenylbenzotriazole class developed for coatings(95% benzenepropanoic acid,3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-, C7-9-branchedand linear alkyl esters and 5% 1-methoxy-2-propyl acetate). It issuitable for extreme environmental conditions with high performance anddurability. Its broad UV absorption allows efficient protection of basecoats or substrates. The performance of TINUVIN® 384-2 can be enhancedwhen used in combination with a HALS stabilizer such as TINUVIN® 292 or123. These combinations improve the durability by inhibiting orretarding the occurrence of failures such as gloss reduction, cracking,color change, blistering and delamination. TINUVIN® 384-2 is recommendedin concentrations of 1.0-3.0% with 0.5-2.0% TINUVIN® 123, 144 or 292.

[0180] UVITEX® OB is a Ciba Specialty Chemicals fluorescent whiteningagent. It is a high molecular weight low volatility optical brightenerof the thiophenediyl benzoxazole class(2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole)). UVITEX OB hasexceptional whitening properties, good light fastness and a brilliantbluish cast (an absorption peak at ˜380 nm and an emission peak at ˜430nm. The use levels of UVITEX OB range between 0.005-0.1% depending onperformance requirements of the final application. Basically, thebrightening effect is not light stable. It may be used in a variety ofblends and combinations with other UV stabilizers and opticalbrighteners; the concentration of UVITEX OB should be increased whencombined with the TINUVIN UV stabilizers discussed herein.

[0181] GAFSORB UV Absorber 2H4M, A GAF Europe of Surrey, England productobtained from FGI of Australia, is 2-hydroxy-4-methoxy-benzophenone andhas a K-value (absorbency index) at 286 nanometers in methanol of 64.0minimum.

[0182] CHIMASSORB 90, a Ciba Specialty Chemicals product obtained fromFGI of Australia, is a 2-hydroxy-4-methoxybenzophenone UV stabilizer.

[0183] SILQUEST A-174 SILANE, a Crompton Corporation product obtainedfrom OSi Specialties, is an adhesive additive of >98%gamma-methacryloxypropyltrimethoxysilane and <2% related silane estersand methanol.

[0184] BYK-A 501, a product of BYK-Chemie GmbH of Germany obtained fromFGI of Australia is a silicone-free air release additive for unsaturatedpolyesters. BYK-A 501 is a combination of foam destroying polymers usedto prevent air entrapment and porosity in filled and unfilledunsaturated polyester, epoxy and vinyl ester resins. BYK-A 501 ispreferably added prior to fillers or reinforcements, but can be addedinto finished compositions without difficulty.

[0185] Typical fiberglass products used for producing FRP articles canbe utilized. For example, BTI C-24, obtained from Brunswick TechnologiesInc., is a unidirectional non-woven fabric for reinforced plastics (55%fiber content by weight) with high strength and stiffness, reducedreinforcement print transfer to finished surfaces and good laminateproperties. Stitched reinforcing fiberglass was obtained from ACIFibreglass of Victoria, Australia. The stitching process is used tocombine chopped strand mat with roven roving, with nominal weights of900-1400 g/m² utilized in the standard range. PPG Chopped Strand Mat(CSM), available from PPG Industries, Inc., of Pittsburgh, Pa., is≧93.0% fibrous glass, with a composition consisting principally ofsilicon oxide in an amorphous vitreous state. The surface sizing is≦1.0%. The surface binder (polyester) is ≦6.0%. Normally there are nofibers with diameters smaller than 6 microns in PPG chopped strand matproduct.

[0186] CELOGEN® XP-100, a Uniroyal Chemicals product obtained from A. C.Hatrick Chemicals of Botany, NSW, Australia, is a sulfonylhydrazidechemical blowing agent developed for foaming isophthalic, orthophthalicand other resins for varied thermoset polyester applications. CELOGEN®XP-100 foams at ambient temperature and is easily incorporated into thepolyester resin. It is typically added to polyester resins in 2% byweight concentrations prior to addition of the fillers. The foamingaction helps to bring phosphorescent particles to the surface of themolded article; in addition, it helps encapsulates glass fibers (ifutilized), thereby eliminating the need for the resin to be rolled orotherwise forced into the glass.

[0187] The clear casting resins are a helpful additive both as a flowagent and as a suspension additive. The isophthalic and orthophthalicpolyester resins are also useful suspension additives to a base gelcoat.

[0188] It is important that suspending fillers and any other fillers beadded to the polymers to modify the viscosity prior to addition of thephosphorescent pigments. The shrouding effect of the viscous materialhelps prevent damage to the phosphorescent particles.

[0189] When mixing the LUMILUX® or other phosphorescent material intothe resin base, observation of the “skin” of the resin is extremelyuseful in adding the ideal amount. When the ideal amount is added, thegaps in the polymer will be filled in and an iridescence or sheen willbe visible on the surface (and on the surface of a spatula dipped intothe mixture) and the skin looks compacted and dense. Addition of toomuch phosphor causes the mixture to thicken, with the surface becomingfloury and losing its sheen, resulting in an overly dry and brittlematerial with impaired structural and luminescent properties.

[0190] When mixing, an air mixer is generally preferred as it cuts downon the concussion impact and bruising which adversely affects theproperties. A preferred mixer is the jet type mixer 15244 or 15245obtainable from United States Plastic Corp. of Lima, Ohio. As the lightoutput of zinc sulfide luminescent pigments is closely associated withtheir crystalline structure, care should be taken at all stages ofprocessing not to destroy the crystals by mechanical force. In general,a smaller phosphorescent particle is useful for more “compactness” atthe surface.

[0191] The luminescent gel coat may be used for dressing naked fibersand laminating resin on both interior and exterior surfaces. For aparticularly smooth and decorative surface, additional wax and styrenemonomer may be added.

[0192] The luminescent gel coat formulations presented above are appliedto the surface of a mold with a suitable method such as spraying orrolling. After partial curing, the gel-coated film is lined withfiberglass, the desired laminating resins (which may or may not beluminescent) are applied, and the assembly is cured and demolded to forma shaped article with the luminescent gel coat as the surface layer.Similarly, luminescent gel coat may be applied last to form the finishedinterior layer of the article (e.g., the interior of a boat). A suitablenon-luminescent laminating resin for inner, hidden layers is POLYLITE®61-358.

[0193] Release agents may be applied to the mold surface beforefabrication to facilitate the release of the cured laminated product.The release agent should be insoluble and impervious to styrene tofunction well. Polyvinyl alcohol (PVA) solutions form a release filmthat allows excellent replications of the mold surface; for less complexmoldings, natural polishing waxes, including those with a high carnaubacontent, are suitable.

[0194] A foaming agent tends to force the phosphorescent particles tothe surface of the finished molded articles, resulting in excellentluminescent properties. Similarly, injection molding tends to force thephosphor particles to the surface when the luminescent polymersdescribed herein are utilized. For use in injection molding, typically athicker viscosity is preferred than for use as a gel coat.

[0195] Excess trim from moldings is suitable for recycling and reuse inthe luminescent polymers disclosed herein.

[0196] It will be readily apparent to those skilled in the art as to howthe above examples designed for spray processing, open mold processingand injection and blow molding may be modified for utilization in theother processes such as such as pressed laminates, resin transfermolding (RTM) and structural reaction injection molding (S-RIM),compression or matched die molding, filament winding, spin or rotationalmolding, continuous panel process, premix or bulk molding compound,preforms and prepregs, vacuum-bag molding, pressure bag molding,autoclave molding, thermoset pultrusion, pulforming and extrusion. Itwill also be apparent to those skilled in the art as to the factorsnecessary to determine optimum mixtures and conditions in accordancewith the invention disclosed above as variations are made in the coatingor mold processing technology.

[0197] Examples of the invention described above have been made andtested and found to deliver the advantages described. It should beunderstood the foregoing detailed description is for purposes ofillustration rather than limitation of the scope of protection accordedthis invention, and therefore the description should be consideredillustrative, not exhaustive. While the invention has been described inconnection with preferred embodiments, it will be understood that thereis no intention to limit the invention to those embodiments. On thecontrary, it will be appreciated that those skilled in the art, uponattaining an understanding of the invention, may readily conceive ofalterations to, modifications of, and equivalents to the preferredembodiments without departing from the principles of the invention, andit is intended to cover all these alternatives, modifications andequivalents. The scope of the patent protection is to be measured asbroadly as the invention permits. Accordingly, the scope of the presentinvention should be assessed as that of the appended claims and anyequivalents falling within the true spirit and scope of the invention.

I claim:
 87. An electroluminescent polymer comprising a thermosettingpolyester, a suspending filler and an electroluminescent pigment. 88.The electroluminescent polymer of claim 87 wherein theelectroluminescent polymer and a conductive substrate selected from thegroup consisting of metal, glass with a conductive layer and conductivepolymer are formed into layers.
 89. The electroluminescent polymer ofclaim 88 wherein a layer is applied by methods selected from spray,curtain coating, screen printing, spread coating, vacuum deposition, ionplating, sputtering and chemical vapor deposition.
 90. Theelectroluminescent polymer of claim 89 wherein the conductive polymer ismade conductive by materials selected from the group consisting ofconductive fillers and conductive fibers.
 91. The electroluminescentpolymer of claim 90 wherein the conductive fibers comprise stainlesssteel conductive fibers.
 92. The luminescent polymer of claim 87 whereinthe thermosetting polyester is a glycol based thermosetting polyester.93. The luminescent polymer of claim 87 wherein the thermosettingpolyester comprises a glycol component selected from the groupconsisting of propylene glycol, ethylene glycol, neopentyl glycol,diethylene glycol, dipropylene glycol, 1,4-butanediol, dibromoneopentylglycol, 2,2,4-trimethyl-1,3-pentanediol, 1,3-butanediol,1,5-pentanediol, 1,3-propanediol, hexylene glycol, triethylene glycol,tetraethylene glycol and mixtures thereof.
 94. The luminescent polymerof claim 87 wherein the thermosetting polyester comprises a polyhydricalcohol component selected from the group consisting of neopentylglycol, propylene glycol, ethylene glycol, diethylene glycol,dipropylene glycol, dibromoneopentyl glycol, bisphenol dipropoxy ether,2,2,4-trimethylpentane-1,3-diol, tetrabromobisphenol dipropoxy ether,1,4-butanediol, Bisphenol A adducts, hydrogenated Bisphenol A, DCPDhydroxyl adducts and mixtures thereof.
 95. The luminescent polymer ofclaim 87 wherein the suspending filler is selected from the groupconsisting of silica, microspheres, glass fibers and other short fibers,nepheline syenite, feldspar, glass flakes, pumice, mica, calciumcarbonate, magnesium sulfate, calcium sulfate, alumina trihydrate andmixtures thereof.
 96. The electroluminescent polymer of claim 87 whereinthe electroluminescent polymer is coated with a metallic and atransparent conductor.
 97. An electroluminescent device comprising aconductive layer, an electroluminescent polymer layer and a transparentlayer, wherein the electroluminescent polymer layer comprises athermosetting polyester, electroluminescent pigments and a suspendingfiller.